Re: master 8a88f3ed5ae: Add `outline-occur' command and `display-buffer-default-alist' variable

>>> It sounds like we may be able to use display-buffer-default-alist to fix
>>> bug#81233 better than the current workaround?
>>
>> Indeed, this should work just fine:
>
> Thanks.  I think we can also strip out the
> without-local-variable-queries from that function now?

It's unexpected for users to pop up a window with queries for
a background operation, so let's keep without-local-variable-queries.

PS: I realized now we have a problem with using
'display-buffer-default-alist' in 'vc-dir--count-outgoing'.
Because a user might have customized 'display-buffer-alist'
for the category 'vc-log'.  Thus the user customization will
override the let-binding in 'vc-dir--count-outgoing'.

Thus we need a new variable like 'display-buffer-overriding-action',
but with both condition and action like in 'display-buffer-alist'.
So the complete precedence should look like this:

  • The variable ‘display-buffer-overriding-action’.
  • The variable ‘display-buffer-overriding-alist’.   NEW!
  • The user option ‘display-buffer-alist’.
  • The variable ‘display-buffer-default-alist’.
  • The ACTION argument.
  • The user option ‘display-buffer-base-action’.
  • The constant ‘display-buffer-fallback-action’.