bug#50658: Error messages including function names violates coding conventions

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sat, 18 Sep 2021 05:49:37 -0700
> Cc: 50658@debbugs.gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Thanks.  If we are going to show examples (which is a good idea, IMO),
> > I think we should show both examples with and without the function
> > name, and therefore some wording about the function name being
> > optional, and that the rule is not applicable to it, is in order.
> 
> OK, that makes sense.  What do you think of this:

LGTM, thanks.