[gtksourceview] css.lang: Highlight comments in vendor-specific at-rules

[Christian Hergert <chergert src gnome org>]

commit c96f2c537ba8d1195dcd21e5fb07818fc44c21c0
Author: Jeffery To <jeffery to gmail com>
Date:   Sat Jun 30 02:55:10 2018 +0800

    css.lang: Highlight comments in vendor-specific at-rules

 data/language-specs/css.lang | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/data/language-specs/css.lang b/data/language-specs/css.lang
index c992eb4a..cad6ca95 100644
--- a/data/language-specs/css.lang
+++ b/data/language-specs/css.lang
@@ -1759,6 +1759,7 @@
       <start>@\%{vendor-specific-identifier-regex}</start>
       <include>
         <context sub-pattern="0" where="start" style-ref="vendor-specific"/>
+        <context ref="comment"/>
         <context ref="at-rule-css-block"/>
         <context ref="at-rule-delimiter"/>
       </include>