bug#22097: Ispell: lazy highlighting doesn't work properly.

[Eli Zaretskii]

> Date: Sat, 5 Dec 2015 16:04:29 +0000
> Cc: 22097@debbugs.gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> Clearly, the "---"s are going to trigger the very first alternative of
> the regexp.  I don't think "bidi.c", of itself, triggers the regexp.

Not bidi.c itself, some text before it.  E.g., I see several counts of
"---" there, which just might do the trick.