Added missing 'space' keyword in syntax of 'border-image-repeat'.

Author: bert-github

css3-background/Overview.src.html

@@ -2405,7 +2405,7 @@ <h3 id="the-border-image-repeat">The 'border-image-repeat' property</h3>
     <td><dfn>border-image-repeat</dfn>
   <tr>
     <th>Value:
-    <td>[ stretch | repeat | round ]{1,2}
+    <td>[ stretch | repeat | round | space ]{1,2}
   <tr>
     <th>Initial:
     <td>stretch