bug#49069: 28.0.50; [PATCH] Use display-buffer for re-builder

[Trust me I am a Doctor]

Juri Linkov <juri@linkov.net> writes:

>> But maybe we don't care at all about user customizations, the point being
>> rather to stop the re-builder window to be stealed by other buffers, and
>> to clean it on kill-buffer, then we could use
>> 'display-buffer-overriding-actions'.
>
> Sorry, preventing the users from customizing windows is the wrong thing.

I don't know really, let me explain my rational : some users have a very
constrained display-buffer-alist and match ".*". You can see such
rational explained at the end of this page :

https://github.com/nex3/perspective-el

This kind of constraint may be even more important for people with low
vision, as emacs poping windows on a display of 40 columns by 9 lines
is very disruptive.

So with a display-buffer-alist matching ".*", the rule will pop the
re-buffer as the main window, and this create a poor interaction :
the targeted buffer not being visible anymore, the re-buffer taking
a full window.

If really the user customization of the display of re-builder is a
thing, I could put a variable as user-customization to split the apple
in two.

But I may be wrong, after all that's not my case.
Anyway I put a pop-to-buffer in the last patch where I should kept
display-buffer.