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
diff --git a/Documentation/cmd-ls-user-refs.txt b/Documentation/cmd-ls-user-refs.txt
index bd59f75..11781de 100644
--- a/Documentation/cmd-ls-user-refs.txt
+++ b/Documentation/cmd-ls-user-refs.txt
@@ -1,12 +1,9 @@
-gerrit ls-user-refs
-===================
+= gerrit ls-user-refs
 
-NAME
-----
+== NAME
 gerrit ls-user-refs - List refs visible to a specific user
 
-SYNOPSIS
---------
+== SYNOPSIS
 --
 'ssh' -p <port> <host> 'gerrit ls-user-refs'
   [--project PROJECT> | -p <PROJECT>]
@@ -14,8 +11,7 @@
   [--only-refs-heads]
 --
 
-DESCRIPTION
------------
+== DESCRIPTION
 Displays all refs that the specified user can see.
 
 Allows an administrator to query which refs are visible for
@@ -24,12 +20,10 @@
 verify that certain secret refs are not exposed to the wrong
 groups.
 
-ACCESS
-------
+== ACCESS
 Administrators
 
-OPTIONS
--------
+== OPTIONS
 --project::
 -p::
 	Required; Name of the project for which the refs should be listed.
@@ -43,8 +37,7 @@
 --only-refs-heads::
 	Only list the refs found under refs/heads/*
 
-EXAMPLES
---------
+== EXAMPLES
 
 List visible refs for the user "mr.developer" in project "gerrit"
 =====