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

[martin rudalics]

> The function 'display-warning' has the argument 'buffer-name'.
> This means it's impossible to match the buffer name in
> 'display-buffer-alist', because the buffer name can be anything.
> Therefore the 'category' should be added to the 'display-buffer'
> call in 'display-warning'.
>
> Currently the warning buffer is displayed in a random place
> in horizontally split windows.

'display-buffer' never chooses a random place.

> The change is needed to display it
> in the consistent place.  This change is accompanied with adding
> the category for the case if someone don't like this change
> (very unlikely) and wants to revert it to display the buffer
> in a random place.  It will be possible to customize this
> by using the category in 'display-buffer-alist'.

I agree with everything else Juri says here.

martin