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

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 03 Jan 2019 23:29:18 +0200
> Cc: 33870@debbugs.gnu.org, Dmitry Gutov <dgutov@yandex.ru>
> 
> when xref-find-definitions pops up the xref window, usually it
> contains just 2 lines taking half of the screen where most space is
> uselessly empty.

We have fit-window-to-buffer for these situations.

> The distinction between internal and public window functions is quite fuzzy.

To my mind, internal functions shouldn't be used outside of the file
that defines them.