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

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 33870@debbugs.gnu.org,  dgutov@yandex.ru
> Date: Thu, 27 Dec 2018 01:17:00 +0200
> 
> Since we have a convention that code displaying a buffer in the
> window have to obey display actions that are customizable by
> `display-buffer-alist', `display-buffer-overriding-action',
> and other display related variables (e.g. like implemented
> recently with switch-to-buffer-obey-display-actions),
> I see no reason why *xref* should differ from *grep* or *Occur*.
> It should not involve more complexity than necessary.

We are under no obligation to maintain 100% consistency between
different commands, just because some of their aspects are similar.
I'd like to hear of specific real-life situations where the current
code doesn't DTRT, before I'd agree to a change in this area.