bug#51210: Customizable other-window-for-scrolling

[Juri Linkov]

>> There are also nice commands: M-<home> (beginning-of-buffer-other-window)
>> and M-<end> (end-of-buffer-other-window), but for no reason they recenter
>> the other window after moving to the beginning/end.
>> 
>> It would be better to remove this disservice:
>
> This is age-old behavior.  Why change it because you happen to dislike
> it?

The problem is that with its current implementation, it's unusable:
when the window height is 75 lines, then typing M-<end> leaves
half-screen empty.

But fortunately this can be fixed since Emacs 28 introduced a new key
C-M-S-l to recenter the other window, so it's now easy to type it
when the user needs to recenter the other window.