bug#12204: 24.1.50; Binding mouse-movement interferes with "C-h c" for mouse clicks

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@users.sourceforge.net>
> Date: Mon, 12 Jun 2017 13:15:24 -0400
> Cc: 12204@debbugs.gnu.org
> 
> > I was actually thinking seriously to not show the help message for
> > mouse-movement bindings.  Would that break something important?
> 
> It should only break discovery of what's bound to <mouse-movement> I
> guess, and we could still leave "C-h k" for that so it shouldn't be
> much of a problem.

Then I think this is what we should do, and perhaps leave some knob to
get back the old behavior.