bug#16491: 24.3.50; REGRESSION: `defadvice' doc removed from Elisp manual

[Drew Adams <drew.adams@oracle.com>]

Elisp manual node `Advising Emacs Lisp Functions' has been rewritten to
include the new `add-function' stuff.  It is fine to document that new
feature.

What's not fine is to simply remove all of the doc about the traditional
`defadvice' advice system.  Even if that feature is to be deprecated,
its doc should remain until it is desupported.  If this removal is not
a temporary oversight (mistake) then it is quite misguided.  It hurts
Emacs users.

The Elisp manual should continue to be usable to help users code
`defadvice' advice, in addition to `add-function' advice.  As one use
case, some users will use Emacs 24.4 to write or maintain code for
older or multiple Emacs versions.

Normally there is a reasonably long transition period before a feature,
especially a major feature such as `defadvice', is desupported.  And
until desupport, the deprecated feature remains SUPPORTED - in
particular, by continuing to provide users with its reference doc.


In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2014-01-17 on ODIEONE
Bzr revision: 116059 michael.albinus@gmx.de-20140117182409-gz695p2c951idlee
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 'CFLAGS=-O0 -g3' LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'