bug#14623: Some broken links in HTML node of Emacs manual

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 15 Jun 2013 16:14:59 +0800
> From: Xue Fuqiao <xfq.free@gmail.com>
> 
> There are some broken links:
> 
> `movemail' and `URL' in
> http://www.gnu.org/software/emacs/manual/html_node/emacs/Movemail.html
> 
> `Aspell' in
> http://www.gnu.org/software/emacs/manual/html_node/emacs/Spelling.html
> 
> All of them are references to non-Emacs manuals.
> 
> (I'm sorry but I'm not sure whether this is the right place to report
> this problem.  Maybe bug-texinfo is better.)

The links produced in the HTML version of the manual assume that the
target manual will be in the same place.  If that's not guaranteed,
one should use @uref for the HTML version, something like this:

  Rmail uses the @code{movemail} program to move mail from your inbox to
your Rmail file (@pxref{Rmail Inbox}).  When loaded for the first time,
Rmail attempts to locate the @code{movemail} program and determine its
version.  There are two versions of the @code{movemail} program: the
native one, shipped with GNU Emacs (the ``emacs version'') and the one
included in GNU mailutils
@ifhtml
(@uref{http://mailutils.org/manual/, the ``mailutils version''}).
@end ifhtml
@ifnothtml
(the ``mailutils version'', @pxref{movemail,,,mailutils,GNU mailutils}).
@end ifnothtml
They support the same command line syntax and the same basic subset of
options.  However, the Mailutils version offers additional features.