Use the new section title style in Asciidoctor.

We previous use the section title style like:

Section level 1
===============

Section level 2
---------------

Which have a problem in Asciidoctor that the number of "="s or "-"s must match
the number of characters in the header exactly, as a result it's easy to make
mistakes while changing the titles. Asciidoctor provides a better style like:

= Section level 1

== Section level 2

So we switched to this style.

Also fixed a bug in replace_macros.py, which will not cause any problem in the
old style.

Change-Id: I811dd7238735d98f662767c17086152cd69aea02

Documentation/cmd-set-project-parent.txt

@@ -1,12 +1,9 @@
-gerrit set-project-parent
-=========================
+= gerrit set-project-parent
 
-NAME
-----
+== NAME
 gerrit set-project-parent - Change the project permissions are inherited from.
 
-SYNOPSIS
---------
+== SYNOPSIS
 --
 'ssh' -p <port> <host> 'gerrit set-project-parent'
   [--parent <NAME>]
@@ -15,23 +12,19 @@ SYNOPSIS
   <NAME> ...
 --
 
-DESCRIPTION
------------
+== DESCRIPTION
 Changes the project that permissions are inherited through.
 Every project inherits permissions from another project, by
 default this is `All-Projects`.  This command sets
 the project to inherit through another one.
 
-ACCESS
-------
+== ACCESS
 Caller must be a member of the privileged 'Administrators' group.
 
-SCRIPTING
----------
+== SCRIPTING
 This command is intended to be used in scripts.
 
-OPTIONS
--------
+== OPTIONS
 --parent::
 	Name of the parent to inherit through. If not specified,
 	the parent is set back to the default `All-Projects`.
@@ -49,8 +42,7 @@ OPTIONS
 	specifying the --exclude option multiple times. Excluding a
 	project that is not a child project has no effect.
 
-EXAMPLES
---------
+== EXAMPLES
 Configure `kernel/omap` to inherit permissions from `kernel/common`:
 
 ====
@@ -64,8 +56,7 @@ Reparent all children of `myParent` to `myOtherParent`:
 	  --children-of myParent --parent myOtherParent
 ====
 
-SEE ALSO
---------
+== SEE ALSO
 
 * link:access-control.html[Access Controls]