revert-buffer yes-or-no-p should allow "?" too

[Dan Jacobson]

This important question,
"Revert buffer from file .... ?"
is not phrased in clear enough words for the user to understand what
is about to happen.

I like the disabled-command stuff that pops open half the window,
explaining one per line, the consequences of y, n, etc.

Especially as the user can't consult the documentation without
interrupting the question, unless he has another window somewhere.

Why of course, the revert-buffer function is full of y-or-n-p,
yes-or-no-p. Well, a "?" choice should also be allowed on the more
critical questions, giving a description of the consequences.