bug#50880: Add "Contributing to Emacs" help command (see C-h C-h)

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: stefan@marxist.se,  gregory@heytings.org,  50880@debbugs.gnu.org
> Date: Fri, 01 Oct 2021 12:32:54 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> No, this is the `C-h C-h' buffer output.
> >
> > But then all of those are already there?
> 
> Not the "Contributing" one, which is why we're discussing adding a key
> stroke to it so that it'll appear there, too.

And I already said what I think about it: to me it sounds like a waste
to reserve a C-h key for that.  It doesn't even belong to "help" per
se, IMO.