bug#33799: 27.0.50; set-foreground-color completion shows background colors

[Lars Ingebrigtsen]

Glenn Morris <rgm@gnu.org> writes:

>> shows a completion list of colors with different backgrounds, not
>> foregrounds as it would be natural to expect
>
> Very lightly tested:
>
> --- i/lisp/faces.el
> +++ w/lisp/faces.el

I respun the patch for the current trunk and tested it, and I think it
looks really good, so I pushed it to Emacs 28 (with some minor changes).

There was then some discussion about whether
defined-colors-with-face-attributes should have a parameter that says
whether to do readable colours for the "other" colour, and that may be a
good idea, but I don't quite see how that'd be exposed to the user, so I
think we can leave that as is (at least for now).  (And see whether
anybody wants any changes here.)

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no