bug#27979: tab completion for "(yes or no)?"

[Tino Calancha]

On Sun, 6 Aug 2017, Drew Adams wrote:

> > Some experts have in their Emacs init file:
> >   (fset 'yes-or-no-p 'y-or-n-p)
> > So that they will be prompted with (y or n).
>
> More newbies than experts, methinks. ;-)

I have:
(defalias 'yes-or-no-p 'y-or-n-p)

so i am neither expert nor beginner (an outsider or a secret
agent, maybe).