bug#26742: Display bug with composed strings

[Eli Zaretskii]

> Cc: 26742@debbugs.gnu.org
> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
> Date: Wed, 3 May 2017 01:20:17 -0400
> 
> On 2017-05-02 13:57, Eli Zaretskii wrote:
> > Does the problem affect other characters as well, or just these two?
> 
> It seems to affect any pair of characters (I tried using (set-fontset-font t 
> '(?← . ?←) (font-spec :name "Symbola") nil) and this prop line:
> 
>   -*- prettify-symbols-alist: (("R_PO" . (?A (Br . cl) ?←))); -*-

Thanks.  Please try the changes proposed by Ymamoto-san.