Omit edition numbers and dates in manuals

These seem to cause more confusion than they cure; e.g.,
https://shop.fsf.org/books/gnu-emacs-manual-18th-edition-v-261
currently advertises "18th edition" even as it points to
https://www.gnu.org/software/emacs/manual/pdf/emacs.pdf
which says "Seventeenth Edition".  It is simpler and less
confusing to stick to one version number like "26.3".  If we
need a separate edition number for each printed manual for
some reason (marketing?) we can put “@ifset printed-edition”
around anything specific to the printed editions.
(as opposed to online PDF copies).
* doc/emacs/emacs.texi (EDITION):
* doc/lispintro/emacs-lisp-intro.texi (edition-number, update-date):
* doc/lispref/elisp.texi (VERSION, DATE):
Remove, and remove uses.

doc/emacs/emacs.texi

@@ -3,28 +3,10 @@
 @setfilename ../../info/emacs.info
 @settitle GNU Emacs Manual
 @include docstyle.texi
-
-@c The edition number appears in more than one place in this file
-@c I don't really know what it means...
-@c For example, it has said "Sixteenth" since sometime in the Emacs 22
-@c series, all through 23, and into 24.  So it is not very useful IMO,
-@c and offers nothing that EMACSVER does not.  I guess it relates
-@c mainly to the published book sold by the FSF.  Hence no longer
-@c bother including it except iftex.  Really, I think it should not be
-@c here at all (since anyone can make a pdf version), but should just
-@c be something added by the FSF during the publishing process.
-@c Also, the lispref uses a float (3.0), whereas this uses an ordinal,
-@c so the format is not even consistent.
-@set EDITION   Seventeenth
 @include emacsver.texi
 
 @copying
-@iftex
-This is the @value{EDITION} edition of the @cite{GNU Emacs Manual},@*
-@end iftex
-@ifnottex
 This is the @cite{GNU Emacs Manual},
-@end ifnottex
 updated for Emacs version @value{EMACSVER}.
 
 Copyright @copyright{} 1985--1987, 1993--2019 Free Software Foundation, Inc.
@@ -82,7 +64,7 @@ developing GNU and promoting software freedom.''
 @sp 6
 @center @titlefont{GNU Emacs Manual}
 @sp 4
-@center @value{EDITION} Edition, Updated for Emacs Version @value{EMACSVER}.
+@center Updated for Emacs Version @value{EMACSVER}
 @sp 5
 @center Richard Stallman et al.
 @page

doc/lispintro/emacs-lisp-intro.texi

@@ -63,10 +63,6 @@
 \global\hbadness=6666 % don't worry about not-too-underfull boxes
 @end tex
 
-@c These refer to the printed book sold by the FSF.
-@set edition-number 3.10
-@set update-date 28 October 2009
-
 @c For next or subsequent edition:
 @c   create function using with-output-to-temp-buffer
 @c   create a major mode, with keymaps
@@ -106,9 +102,6 @@
 This is @cite{An Introduction to Programming in Emacs Lisp}, for
 people who are not programmers.
 @sp 1
-@iftex
-Edition @value{edition-number}, @value{update-date}
-@end iftex
 @ifnottex
 Distributed with Emacs version @value{EMACSVER}.
 @end ifnottex

doc/lispref/elisp.texi

@@ -52,12 +52,7 @@
 @end ifset
 @end tex
 
-
-@c Version of the manual and of Emacs.
-@c (See comments for EDITION in emacs.texi)
-@set VERSION  3.1
 @include emacsver.texi
-@set DATE October 2014
 
 @c in general, keep the following line commented out, unless doing a
 @c copy of this manual that will be published.  The manual should go
@@ -91,12 +86,7 @@
 @c @syncodeindex tp fn
 
 @copying
-@iftex
-This is edition @value{VERSION} of the @cite{GNU Emacs Lisp Reference Manual},@*
-@end iftex
-@ifnottex
-This is the @cite{GNU Emacs Lisp Reference Manual}
-@end ifnottex
+This is the @cite{GNU Emacs Lisp Reference Manual},
 corresponding to Emacs version @value{EMACSVER}.
 
 Copyright @copyright{} 1990--1996, 1998--2019 Free Software Foundation, Inc.
@@ -127,7 +117,6 @@ developing GNU and promoting software freedom.''
 @subtitle @value{voltitle}
 @end ifset
 @subtitle For Emacs Version @value{EMACSVER}
-@subtitle Revision @value{VERSION}, @value{DATE}
 
 @author by Bil Lewis, Dan LaLiberte, Richard Stallman,
 @author the GNU Manual Group, et al.