bug#14574: prog-prettify-symbols breaks font-locking

[Eli Zaretskii]

> From: Juanma Barranquero <lekktu@gmail.com>
> Date: Sun, 16 Jun 2013 18:18:03 +0200
> Cc: dgutov@yandex.ru, 14574@debbugs.gnu.org
> 
> On Sun, Jun 16, 2013 at 6:14 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > Why do you think it could do that?
> 
> Because I know nothing about redisplay, and because checking
> composition plus some other property sounds like more work than just
> checking on composition. OTOH, I don't know what I'm talking about, so
> I will be very happy to know that we could add a font-lock specific
> composition property alias and not affect performance...

The best way is just try it and see.