bug#34723: 27.0.50; customize and improve diff-mode recentering

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> Sometimes it's also not eager enough (if the hunk is longer than half of
>> the screen, it shouldn't just recenter but it should likely scroll
>> further so that more than half of the screen shows the hunk).
> Yes.  In that specific case, we could call (recenter 0) to make more
> (or all of) the hunk visible.

I think in some cases I'd like it, yes.  But would you?
I thought you didn't want recentering in next-hunk at all‽
Also I'm not sure if it would annoy me more often than not, which is
probably why I haven't bothered to try and code it up.

>> Did that only refer to `scroll-conservatively`?  If not, could you
>> clarify which scroll-related variable setting is not respected,
>> and when?
> Hm, I'm not sure if there was another variable that the behavior
> affects (can't find one now).  This is no big issue; it's an argument
> for making the behavior customizable.

Yes, feel free to add such a custom var.


        Stefan