bug#27980: disabled-command-function should accept ^G

[Tino Calancha]

On Sun, 6 Aug 2017, 積丹尼 Dan Jacobson wrote:

> OK ^G is working again for me now.
>
> Well my only request now is ^G should be listed along with the rest of the keys.
Well, C-g is somehow an universal way of cancel whatever interactive 
command.  It's assumed that any kind of prompt can be safely canceled with C-g.
That is  from lesson #1 in Emacs; i don't think we need to mention it in 
every prompt.