Use list tables

Reformat overlong table into a list-table to make it easier to edit.
The change contains no wording changes besides giving titles to the
list-tables.

Fix formatting for setup-devstack-source-dirs so that the variable does
not get displayed with a grey bar at
https://docs.openstack.org/devstack/latest/zuul_roles.html#role-setup-devstack-source-dirs

Change-Id: I7378d46c507b1d86f1d5319655a55f2a8c5a8f60
diff --git a/doc/source/zuul_ci_jobs_migration.rst b/doc/source/zuul_ci_jobs_migration.rst
index ed97d4c..17e7e16 100644
--- a/doc/source/zuul_ci_jobs_migration.rst
+++ b/doc/source/zuul_ci_jobs_migration.rst
@@ -180,123 +180,147 @@
 devstack-gate defined a default value. In ansible jobs the default is either the
 value defined in the parent job, or the default from DevStack, if any.
 
-==============================================  ============= ==================
-DevStack gate flag                              Repo          New implementation
-==============================================  ============= ==================
-OVERRIDE_ZUUL_BRANCH                            zuul          override-checkout:
-                                                              [branch]
-                                                              in the job definition.
-DEVSTACK_GATE_NET_OVERLAY                       zuul-jobs     A bridge called
-                                                              br-infra is set up for
-                                                              all jobs that inherit
-                                                              from multinode with
-                                                              a dedicated `bridge role <https://zuul-ci.org/docs/zuul-jobs/general-roles.html#role-multi-node-bridge>`_.
-DEVSTACK_GATE_FEATURE_MATRIX                    devstack-gate ``test_matrix_features``
-                                                              variable of the
-                                                              test-matrix role in
-                                                              devstack-gate. This
-                                                              is a temporary
-                                                              solution, feature
-                                                              matrix will go away.
-                                                              In the future services
-                                                              will be defined in
-                                                              jobs only.
-DEVSTACK_CINDER_VOLUME_CLEAR                    devstack      *CINDER_VOLUME_CLEAR: true/false*
-                                                              in devstack_localrc
-                                                              in the job vars.
-DEVSTACK_GATE_NEUTRON                           devstack      True by default. To
-                                                              disable, disable all
-                                                              neutron services in
-                                                              devstack_services in
-                                                              the job definition.
-DEVSTACK_GATE_CONFIGDRIVE                       devstack      *FORCE_CONFIG_DRIVE: true/false*
-                                                              in devstack_localrc
-                                                              in the job vars.
-DEVSTACK_GATE_INSTALL_TESTONLY                  devstack      *INSTALL_TESTONLY_PACKAGES: true/false*
-                                                              in devstack_localrc
-                                                              in the job vars.
-DEVSTACK_GATE_VIRT_DRIVER                       devstack      *VIRT_DRIVER: [virt driver]*
-                                                              in devstack_localrc
-                                                              in the job vars.
-DEVSTACK_GATE_LIBVIRT_TYPE                      devstack      *LIBVIRT_TYPE: [libvirt type]*
-                                                              in devstack_localrc
-                                                              in the job vars.
-DEVSTACK_GATE_TEMPEST                           devstack      Defined by the job
-                                                tempest       that is used. The
-                                                              ``devstack`` job only
-                                                              runs devstack.
-                                                              The ``devstack-tempest``
-                                                              one triggers a Tempest
-                                                              run as well.
-DEVSTACK_GATE_TEMPEST_FULL                      tempest       *tox_envlist: full*
-                                                              in the job vars.
-DEVSTACK_GATE_TEMPEST_ALL                       tempest       *tox_envlist: all*
-                                                              in the job vars.
-DEVSTACK_GATE_TEMPEST_ALL_PLUGINS               tempest       *tox_envlist: all-plugin*
-                                                              in the job vars.
-DEVSTACK_GATE_TEMPEST_SCENARIOS                 tempest       *tox_envlist: scenario*
-                                                              in the job vars.
-TEMPEST_CONCURRENCY                             tempest       *tempest_concurrency: [value]*
-                                                              in the job vars. This
-                                                              is available only on
-                                                              jobs that inherit from
-                                                              ``devstack-tempest``
-                                                              down.
-DEVSTACK_GATE_TEMPEST_NOTESTS                   tempest       *tox_envlist: venv-tempest*
-                                                              in the job vars. This
-                                                              will create Tempest
-                                                              virtual environment
-                                                              but run no tests.
-DEVSTACK_GATE_SMOKE_SERIAL                      tempest       *tox_envlist: smoke-serial*
-                                                              in the job vars.
-DEVSTACK_GATE_TEMPEST_DISABLE_TENANT_ISOLATION  tempest       *tox_envlist: full-serial*
-                                                              in the job vars.
-                                                              *TEMPEST_ALLOW_TENANT_ISOLATION: false*
-                                                              in devstack_localrc in
-                                                              the job vars.
-==============================================  ============= ==================
+.. list-table:: **DevStack Gate Flags**
+   :widths: 20 10 60
+   :header-rows: 1
+
+   * - DevStack gate flag
+     - Repo
+     - New implementation
+   * - OVERRIDE_ZUUL_BRANCH
+     - zuul
+     - override-checkout: [branch] in the job definition.
+   * - DEVSTACK_GATE_NET_OVERLAY
+     - zuul-jobs
+     - A bridge called br-infra is set up for all jobs that inherit
+       from multinode with a dedicated `bridge role
+       <https://zuul-ci.org/docs/zuul-jobs/general-roles.html#role-multi-node-bridge>`_.
+   * - DEVSTACK_GATE_FEATURE_MATRIX
+     - devstack-gate
+     - ``test_matrix_features`` variable of the test-matrix role in
+       devstack-gate. This is a temporary solution, feature matrix
+       will go away. In the future services will be defined in jobs
+       only.
+   * - DEVSTACK_CINDER_VOLUME_CLEAR
+     - devstack
+     - *CINDER_VOLUME_CLEAR: true/false* in devstack_localrc in the
+       job vars.
+   * - DEVSTACK_GATE_NEUTRON
+     - devstack
+     - True by default. To disable, disable all neutron services in
+       devstack_services in the job definition.
+   * - DEVSTACK_GATE_CONFIGDRIVE
+     - devstack
+     - *FORCE_CONFIG_DRIVE: true/false* in devstack_localrc in the job
+       vars.
+   * - DEVSTACK_GATE_INSTALL_TESTONLY
+     - devstack
+     - *INSTALL_TESTONLY_PACKAGES: true/false* in devstack_localrc in
+       the job vars.
+   * - DEVSTACK_GATE_VIRT_DRIVER
+     - devstack
+     - *VIRT_DRIVER: [virt driver]* in devstack_localrc in the job
+       vars.
+   * - DEVSTACK_GATE_LIBVIRT_TYPE
+     - devstack
+     - *LIBVIRT_TYPE: [libvirt type]* in devstack_localrc in the job
+       vars.
+   * - DEVSTACK_GATE_TEMPEST
+     - devstack and tempest
+     - Defined by the job that is used. The ``devstack`` job only runs
+       devstack. The ``devstack-tempest`` one triggers a Tempest run
+       as well.
+   * - DEVSTACK_GATE_TEMPEST_FULL
+     - tempest
+     - *tox_envlist: full* in the job vars.
+   * - DEVSTACK_GATE_TEMPEST_ALL
+     - tempest
+     - *tox_envlist: all* in the job vars.
+   * - DEVSTACK_GATE_TEMPEST_ALL_PLUGINS
+     - tempest
+     - *tox_envlist: all-plugin* in the job vars.
+   * - DEVSTACK_GATE_TEMPEST_SCENARIOS
+     - tempest
+     - *tox_envlist: scenario* in the job vars.
+   * - TEMPEST_CONCURRENCY
+     - tempest
+     - *tempest_concurrency: [value]* in the job vars. This is
+       available only on jobs that inherit from ``devstack-tempest``
+       down.
+   * - DEVSTACK_GATE_TEMPEST_NOTESTS
+     - tempest
+     - *tox_envlist: venv-tempest* in the job vars. This will create
+       Tempest virtual environment but run no tests.
+   * - DEVSTACK_GATE_SMOKE_SERIAL
+     - tempest
+     - *tox_envlist: smoke-serial* in the job vars.
+   * - DEVSTACK_GATE_TEMPEST_DISABLE_TENANT_ISOLATION
+     - tempest
+     - *tox_envlist: full-serial* in the job vars.
+       *TEMPEST_ALLOW_TENANT_ISOLATION: false* in devstack_localrc in
+       the job vars.
+
 
 The following flags have not been migrated yet or are legacy and won't be
 migrated at all.
 
-=====================================  ======  ==========================
-DevStack gate flag                     Status  Details
-=====================================  ======  ==========================
-DEVSTACK_GATE_TOPOLOGY                 WIP     The topology depends on the base
-                                               job that is used and more
-                                               specifically on the nodeset
-                                               attached to it. The new job
-                                               format allows project to define
-                                               the variables to be passed to
-                                               every node/node-group that exists
-                                               in the topology. Named topologies
-                                               that include the nodeset and the
-                                               matching variables can be defined
-                                               in the form of base jobs.
-DEVSTACK_GATE_GRENADE                  TBD     Grenade Zuul V3 jobs will be
-                                               hosted in the grenade repo.
-GRENADE_BASE_BRANCH                    TBD     Grenade Zuul V3 jobs will be
-                                               hosted in the grenade repo.
-DEVSTACK_GATE_NEUTRON_DVR              TBD     Depends on multinode support.
-DEVSTACK_GATE_EXERCISES                TBD     Can be done on request.
-DEVSTACK_GATE_IRONIC                   TBD     This will probably be implemented
-                                               on ironic side.
-DEVSTACK_GATE_IRONIC_DRIVER            TBD     This will probably be implemented
-                                               on ironic side.
-DEVSTACK_GATE_IRONIC_BUILD_RAMDISK     TBD     This will probably be implemented
-                                               on ironic side.
-DEVSTACK_GATE_POSTGRES                 Legacy  This flag exists in d-g but the
-                                               only thing that it does is
-                                               capture postgres logs. This is
-                                               already supported by the roles in
-                                               post, so the flag is useless in
-                                               the new jobs. postgres itself can
-                                               be enabled via the
-                                               devstack_service job variable.
-DEVSTACK_GATE_ZEROMQ                   Legacy  This has no effect in d-g.
-DEVSTACK_GATE_MQ_DRIVER                Legacy  This has no effect in d-g.
-DEVSTACK_GATE_TEMPEST_STRESS_ARGS      Legacy  Stress is not in Tempest anymore.
-DEVSTACK_GATE_TEMPEST_HEAT_SLOW        Legacy  This is not used anywhere.
-DEVSTACK_GATE_CELLS                    Legacy  This has no effect in d-g.
-DEVSTACK_GATE_NOVA_API_METADATA_SPLIT  Legacy  This has no effect in d-g.
-=====================================  ======  ==========================
+.. list-table:: **Not Migrated DevStack Gate Flags**
+   :widths: 20 10 60
+   :header-rows: 1
+
+   * - DevStack gate flag
+     - Status
+     - Details
+   * - DEVSTACK_GATE_TOPOLOGY
+     - WIP
+     - The topology depends on the base job that is used and more
+       specifically on the nodeset attached to it. The new job format
+       allows project to define the variables to be passed to every
+       node/node-group that exists in the topology. Named topologies
+       that include the nodeset and the matching variables can be
+       defined in the form of base jobs.
+   * - DEVSTACK_GATE_GRENADE
+     - TBD
+     - Grenade Zuul V3 jobs will be hosted in the grenade repo.
+   * - GRENADE_BASE_BRANCH
+     - TBD
+     - Grenade Zuul V3 jobs will be hosted in the grenade repo.
+   * - DEVSTACK_GATE_NEUTRON_DVR
+     - TBD
+     - Depends on multinode support.
+   * - DEVSTACK_GATE_EXERCISES
+     - TBD
+     - Can be done on request.
+   * - DEVSTACK_GATE_IRONIC
+     - TBD
+     - This will probably be implemented on ironic side.
+   * - DEVSTACK_GATE_IRONIC_DRIVER
+     - TBD
+     - This will probably be implemented on ironic side.
+   * - DEVSTACK_GATE_IRONIC_BUILD_RAMDISK
+     - TBD
+     - This will probably be implemented on ironic side.
+   * - DEVSTACK_GATE_POSTGRES
+     - Legacy
+     - This flag exists in d-g but the only thing that it does is
+       capture postgres logs. This is already supported by the roles
+       in post, so the flag is useless in the new jobs. postgres
+       itself can be enabled via the devstack_service job variable.
+   * - DEVSTACK_GATE_ZEROMQ
+     - Legacy
+     - This has no effect in d-g.
+   * - DEVSTACK_GATE_MQ_DRIVER
+     - Legacy
+     - This has no effect in d-g.
+   * - DEVSTACK_GATE_TEMPEST_STRESS_ARGS
+     - Legacy
+     - Stress is not in Tempest anymore.
+   * - DEVSTACK_GATE_TEMPEST_HEAT_SLOW
+     - Legacy
+     - This is not used anywhere.
+   * - DEVSTACK_GATE_CELLS
+     - Legacy
+     - This has no effect in d-g.
+   * - DEVSTACK_GATE_NOVA_API_METADATA_SPLIT
+     - Legacy
+     - This has no effect in d-g.