bug#67001: [PATCH] ; Promptly disable 'completion-in-region-mode'

[Juri Linkov]

close 67001 30.0.50
thanks

> This patch addresses an issue that Juri (CC'd) observed in Bug#66948,
> where `completion-at-point` leaves TAB bound to `completion-at-point`
> even when it doesn't show the completions list.
>
> To reproduce:
> 1. emacs -Q
> 2. In the *scratch* buffer, insert the following:
>
> (defun foo ()
> bar
>
> 3. With point after "bar", press C-M-i to invoke `completion-at-point`.
>    This shows a message saying "No match".  That's expected.
> 4. Press TAB.  This again shows a message saying "No match".
>    This is unexpected, instead TAB should indent "bar" as usual.

Thanks for the patch.  This looks like the right way to fix this
issue.  So now pushed to master.