bug#69983: Use category for display-buffer-alist

[Juri Linkov]

>> > More importantly, if we want to let programs and users control where
>> > the warnings are displayed, I'd rather we introduced a new,
>> > warning.el-specific option.  Up front, there's no reason for anyone to
>> > assume that display-buffer-alist will have _any_ effect on
>> > display-warning, because we don't document that display-warning uses
>> > display-buffer.  So we could one day decide to implement the display
>> > of the warnings in an entirely different fashion, and then no
>> > customizations of display-buffer-alist will be able to affect the
>> > display.  In fact, in some situations we already display the warning
>> > other than via display-buffer.
>>
>> These are just excuses to not make life easier for users of
>> horizontally split windows.
>
> I don't see how a warning-specific option could be an "excuse".  It
> can solve the problem you attempt to solve as well as what you
> propose.

There is already the option display-buffer-alist.