Use @set and @value to avoid changing the edition and the Emacs version

number in several places.

man/emacs.texi

@@ -5,11 +5,13 @@
 @setfilename ../info/emacs
 @synindex pg cp
 
-@ifnottex
 @c The edition number appears in several places in this file
-This is the fourteenth edition of the @cite{GNU Emacs Manual},
-updated for Emacs version 21.0.98.
-@c Please REMEMBER to update edition number in *three* places in this file.
+@set EDITION   Fourteenth
+@set EMACSVER  21.0.98
+
+@ifnottex
+This is the @value{EDITION} edition of the @cite{GNU Emacs Manual},
+updated for Emacs version @value{EMACSVER}.
 
 @dircategory Emacs
 @direntry
@@ -52,7 +54,7 @@ Software Foundation raise funds for GNU development.''
 @sp 6
 @center @titlefont{GNU Emacs Manual}
 @sp 4
-@center Fourteenth Edition, Updated for Emacs Version 21.0.98.
+@center @value{EDITION} Edition, Updated for Emacs Version @value{EMACSVER}.
 @sp 5
 @center Richard Stallman
 @page
@@ -60,8 +62,8 @@ Software Foundation raise funds for GNU development.''
 Copyright @copyright{} 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
    Free Software Foundation, Inc.
 @sp 2
-Fourteenth Edition @*
-Updated for Emacs Version 21.0.98, @*
+@value{EDITION} Edition @*
+Updated for Emacs Version @value{EMACSVER}, @*
 August 2000
 
 ISBN 1-882114-06-X
@@ -94,7 +96,8 @@ Cover art by Etienne Suvasa.
 
 Emacs is the extensible, customizable, self-documenting real-time
 display editor.  This Info file describes how to edit with Emacs and
-some of how to customize it; it corresponds to GNU Emacs version 21.1.
+some of how to customize it; it corresponds to GNU Emacs version
+@value{EMACSVER}.
 For information on extending Emacs, see @ref{,Emacs Lisp,, elisp, The
 Emacs Lisp Reference Manual}.
 @end ifnottex