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/rest-api-access.txt

@@ -1,17 +1,14 @@
-Gerrit Code Review - /access/ REST API
-======================================
+= Gerrit Code Review - /access/ REST API
 
 This page describes the access rights related REST endpoints.
 Please also take note of the general information on the
 link:rest-api.html[REST API].
 
 [[access-endpoints]]
-Access Rights Endpoints
------------------------
+== Access Rights Endpoints
 
 [[list-access]]
-List Access Rights
-~~~~~~~~~~~~~~~~~~
+=== List Access Rights
 --
 'GET /access/?project=link:rest-api-projects.html#project-name[\{project-name\}]'
 --
@@ -289,8 +286,7 @@ The entries in the map are sorted by project name.
 ----
 
 [[access-section-info]]
-AccessSectionInfo
-~~~~~~~~~~~~~~~~~
+=== AccessSectionInfo
 The `AccessSectionInfo` describes the access rights that are assigned
 on a ref.
 
@@ -304,8 +300,7 @@ entities.
 |==================================
 
 [[permission-info]]
-PermissionInfo
-~~~~~~~~~~~~~~
+=== PermissionInfo
 The `PermissionInfo` entity contains information about an assigned
 permission.
 
@@ -323,8 +318,7 @@ link:#permission-info[PermissionRuleInfo] entities.
 |==================================
 
 [[permission-rule-info]]
-PermissionRuleInfo
-~~~~~~~~~~~~~~~~~~
+=== PermissionRuleInfo
 The `PermissionRuleInfo` entity contains information about a permission
 rule that is assigned to group.
 
@@ -346,8 +340,7 @@ The max value of the permission range.
 |==================================
 
 [[project-access-info]]
-ProjectAccessInfo
-~~~~~~~~~~~~~~~~~
+=== ProjectAccessInfo
 The `ProjectAccessInfo` entity contains information about the access
 rights for a project.