Enforce function declaration format in bash8

Check that function calls look like ^function foo {$ in bash8, and fix
all existing failures of that check.  Add a note to HACKING.rst

Change-Id: Ic19eecb39e0b20273d1bcd551a42fe400d54e938
diff --git a/lib/infra b/lib/infra
index 0dcf0ad..7f70ff2 100644
--- a/lib/infra
+++ b/lib/infra
@@ -27,7 +27,7 @@
 # ------------
 
 # unfubar_setuptools() - Unbreak the giant mess that is the current state of setuptools
-function unfubar_setuptools() {
+function unfubar_setuptools {
     # this is a giant game of who's on first, but it does consistently work
     # there is hope that upstream python packaging fixes this in the future
     echo_summary "Unbreaking setuptools"
@@ -40,7 +40,7 @@
 
 
 # install_infra() - Collect source and prepare
-function install_infra() {
+function install_infra {
     # bring down global requirements
     git_clone $REQUIREMENTS_REPO $REQUIREMENTS_DIR $REQUIREMENTS_BRANCH