bug#42708: Let users copy "*Char Help*" buffer

[Juri Linkov]

> I also wouldn't be happy about wholesale replacement of uses
> of `read-char-choice' by `read-char-from-minibuffer'.
> Maybe it makes sense to replace some such occurrences, but
> it would be good to see some justification case by case.

Actually, only one occurrence of `read-char-choice'
was replaced by `read-char-from-minibuffer'.

> But if `read-char-choice' can itself remain in the
> `read-char', `read-event', `read-key', etc. camp, then at
> least that will be good, IMO.  Thx.

Yes, `read-char-choice' remains in that camp unchanged.