(Autorevert): Add menu descriptions.

doc/emacs/arevert-xtra.texi

@@ -6,7 +6,7 @@
 @c This file is included either in emacs-xtra.texi (when producing the
 @c printed version) or in the main Emacs manual (for the on-line version).
 @node Autorevert
-@section Auto Reverting non-file Buffers
+@section Auto Reverting Non-File Buffers
 
 Global Auto Revert Mode normally only reverts file buffers.  There are
 two ways to auto-revert certain non-file buffers: enabling Auto Revert
@@ -39,9 +39,9 @@ The details depend on the particular types of buffers and are
 explained in the corresponding sections.
 
 @menu
-* Auto Reverting the Buffer Menu::
-* Auto Reverting Dired::
-* Supporting additional buffers::
+* Auto Reverting the Buffer Menu:: Auto Revert of the Buffer Menu.
+* Auto Reverting Dired::           Auto Revert of Dired buffers.
+* Supporting additional buffers::  How to add more Auto Revert support. 
 @end menu
 
 @node Auto Reverting the Buffer Menu