bug#60929: 30.0.50; [FR] `file-name-extension' and backup suffixes

[Eli Zaretskii]

> Cc: 60929@debbugs.gnu.org
> Date: Wed, 18 Jan 2023 14:47:14 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Further, `file-name-extension' returns:
> > 
> >     The extension, in a file name, is the part that begins with the last .,
> >     excluding version numbers and backup suffixes, except that a leading .
> >     of the file name, if there is one, doesn't count.
> 
> This documentation is slightly inaccurate, and thus misleading.  It
> should be fixed.

Now done.