bug#33870: 27.0.50; xref-goto-xref not configurable

[Juri Linkov]

> I attach a version which should handle this now.  I still can't get
> used to a positional specification of direction and reference window
> so ALIST now has to contain separate 'direction' and 'window' entries
> as in
>
> (pop-to-buffer buf '(display-buffer-in-direction (direction . bottom) (window 
> . main)))

Thanks, it works without errors, but for some reason it doesn't fit
the buffer into the window, i.e. the old version

  (pop-to-buffer buf '(display-buffer--maybe-at-bottom))

correctly resized the window, but the new version above doesn't.