bug#32991: 27.0.50; diff-auto-refine-mode a no-op

[Stefan Monnier]

>> Ah, right, makes sense.  Could we fix this more directly by using
>> `called-interactively` instead?
> I think so, though I avoided that function because of the warnings in
> its documentation.

Yes, it's better to avoid it.  But in this case, it's just a temporary
situation in order to cut the patch into two chunks, so it's perfectly fine.

> For a bit of background: I sometimes enable a minor mode in the
> ChangeLog buffer which narrows *vc-diff* (if displayed) to the changes
> of the file at point, like an rmail summary buffer with its
> corresponding message buffer.  I'd like to eventually add this feature
> to add-log.el.  The current diff-hunk-prev/diff-hunk-next change the
> narrowing of the buffer and thus cause some friction with this minor
> mode.

As I said, I don't care much about this restriction "feature" of
diff-hunk-prev/diff-hunk-next, so I think it's OK to just drop it.
If some users then complain, we can see how to re-add it.

> defcustom for it in a second patch (ditto for the re-centering).

But the recentering is more important, IMO.  And I don't quite see why
you'd need a defcustom for it (I can see why you might only do the
recentering when the function is called interactively, tho).


        Stefan