[PATCH] emacs: mua: add a pre-send-check-hook

[Mark Walters]

> For consistency with Emacs' own elisp, perhaps rename
> notmuch-mua-pre-send-check-hooks to
> notmuch-mua-pre-send-check-functions?

Hi

Yes you are correct.  (Annoyingly I had thought about this and thought
it was OK since I didn't need to pass an argument. I had missed the
return value case).

Best wishes

Mark