configuration.rst: Document post-extra meta section phase
Change-Id: I81d121424057fd79c1a0a65d420df3ee1badb6f3
diff --git a/doc/source/configuration.rst b/doc/source/configuration.rst
index 6052576..96f91ec 100644
--- a/doc/source/configuration.rst
+++ b/doc/source/configuration.rst
@@ -56,6 +56,7 @@
before they are started
- **extra** - runs after services are started and before any files in
``extra.d`` are executed
+- **post-extra** - runs after files in ``extra.d`` are executed
The file is processed strictly in sequence; meta-sections may be
specified more than once but if any settings are duplicated the last to