[gtk+] docs: Add missing value syntax for border-image

[Matthias Clasen <matthiasc src gnome org>]

commit f669ccca66e8a59cbdcaeeff58a15e6c9255d843
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Dec 26 16:04:02 2015 -0500

    docs: Add missing value syntax for border-image

 docs/reference/gtk/css.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/gtk/css.xml b/docs/reference/gtk/css.xml
index 8d27bb4..7e11de5 100644
--- a/docs/reference/gtk/css.xml
+++ b/docs/reference/gtk/css.xml
@@ -1747,7 +1747,7 @@ entry {
             </row>
             <row>
               <entry>border‑image</entry>
-              <entry></entry>
+              <entry>〈border-image-source〉 || 〈border-image-slice〉 [ / 〈border-image-width〉 | / 
〈border-image-width〉? / 〈border-image-outset〉 ]? || 〈border-image-repeat〉</entry>
               <entry>see individual properties</entry>
               <entry><ulink url="http://www.w3.org/TR/css3-background/#border-image";>CSS3</ulink></entry>
               <entry></entry>