bug#24861: [PATCH] Fix annoying "Parsing...done" message in c++-mode

[Eli Zaretskii <eliz@gnu.org>]

> From: Hong Xu <hong@topbug.net>
> Cc: 24861@debbugs.gnu.org
> Cc: Andreas Schwab <schwab@linux-m68k.org>
> Date: Wed, 02 Nov 2016 16:34:22 -0700
> 
> On 2016-11-02 Wed 13:21 GMT-0700, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > (Not that I understand why this particular message needs to be
> > customizable.)
> 
> Because the messages by cpp.el is so frequent that it often competes
> with other useful information.

Yes, but we have lots of similar messages in other places.  A search
for a call to 'message' that displays "SOMETHING...done" turns up more
than 270 hits.  Why is this particular package being singled out?

Also, what useful information does it conceal?  Can you show a use
case where this happens?

> I've added some explanation in the docstring.

That should not be necessary, such explanations should be in comments
and commit log messages.

Thanks.