bug#30068: 26.0; REGRESSION: no doc for `x-display-pixel-*'

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: 30068@debbugs.gnu.org
> Date: Sat, 20 Jan 2018 13:14:06 -0500
> 
> >> +          /* Ignore docs that start with SKIP.  These mark
> >> +             placeholders where the real doc is elsewhere.  */
> >
> > This must be in the ELisp manual, of course, and perhaps also in NEWS.
> 
> I don't see why an internal implementation detail that will be
> self-documenting ("SKIP: real doc in xfns.c") needs to be in the
> manual and NEWS, but if you say so.

We need this in the manual so that people who write such doc strings
will know to use this facility in the future.

> Is this change then approved?

I'm okay with it, yes.

Thanks.