bug#57400: 29.0.50; Support sending patches from VC directly

[Juri Linkov]

>> Hmm, I tried both variants, and still not sure which is better
>> for the 1-patch case.  However, what I definitely suggest to do is
>> to get rid of recursive-edit, that also Robert noticed on emacs-devel.
>> recursive-edit is too fragile for modal editing, because such
>> commands as keyboard-escape-quit can easily break it.  Without
>> recursive-edit you can just create all mail buffers at once.
>> Then after sending one mail, its buffer gets buried, and the
>> next mail buffer will be shown instead, etc.
>
> I think you are right, I'll do that and push the changes.

Thanks.  I noticed there is still dangling exit-recursive-edit.