emacs manual patch: refer to File Variables from Numbered Backups.

["Jim Blandy" <jimb@red-bean.com>]

A user reading about backup policies will often have a particular file
in mind whose backup policy he would like to change.

The fact that Rmail mode uses this variable seems out of place.
Perhaps a reader who has noticed Rmail's behavior with regards to
backup files could relate that to the effect of this variable, but
readers unfamiliar with Rmail won't.

* emacs.texi (Numbered Backups): reference File Variables, as well.
Remove discussion of Rmail's implementation.

diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -591,9 +591,9 @@ The usual way to set this variable is gl
 The usual way to set this variable is globally, through your
 @file{.emacs} file or the customization buffer.  However, you can set
 @code{version-control} locally in an individual buffer to control the
-making of backups for that buffer's file.  For example, Rmail mode
-locally sets @code{version-control} to @code{never} to make sure that
-there is only one backup for an Rmail file.  @xref{Locals}.
+making of backups for that buffer's file (@pxref{Locals}).  You can
+have Emacs set @code{version-control} locally whenever you visit a
+given file (@pxref{File Variables}).

 @cindex @env{VERSION_CONTROL} environment variable
   If you set the environment variable @env{VERSION_CONTROL}, to tell