bug#37815: [PATCH] Update FAQ entry on XEmacs

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sat, 19 Oct 2019 13:48:02 +0200
> Cc: 37815@debbugs.gnu.org
> 
> > I think we should keep some of the text that talks about copyright
> > assignment problems in XEmacs sources, in case people would want to
> > borrow some of that code and submit it to Emacs.
> >
> > Otherwise, SGTM, thanks.
> 
> I just kept the old text, since I couldn't find a way to shorten it.
> I'm not sure if there is any code left in XEmacs that we are very keen
> on using these days?  If not, perhaps we could reword it.
> 
> I've attached a tentative patch here.  What do you think?

It's fine, thanks.