bug#15339: 24.3.50; Control characters are displayed as square in describe-char

[Eli Zaretskii]

> From: Jan Djärv <jan.h.d@swipnet.se>
> Date: Thu, 12 Sep 2013 19:24:24 +0200
> Cc: Eli Zaretskii <eliz@gnu.org>,
>  Xue Fuqiao <xfq.free@gmail.com>,
>  15339@debbugs.gnu.org
> 
> > On a text terminal, the character is written literally, which messes up
> > the display (FF has the effect of moving the cursor down).
> > 
> > Andreas.
> 
> Yes, that happens on OSX also.

Perhaps for control characters, the default should be not to show the
decomposition.