[css-transitions-1] Fix warnings about unused definitions

Author: birtles

css-transitions-1/Overview.bs

@@ -1192,19 +1192,19 @@ objects, as <a>event handler IDL attributes</a>:
     <th><a>Event handler event type</a></th>
   </tr>
   <tr>
-    <td><dfn>ontransitionrun</dfn></td>
+    <td>{{GlobalEventHandlers/ontransitionrun}}</td>
     <td><a idl>transitionrun</a></td>
   </tr>
   <tr>
-    <td><dfn>ontransitionstart</dfn></td>
+    <td>{{GlobalEventHandlers/ontransitionstart}}</td>
     <td><a idl>transitionstart</a></td>
   </tr>
   <tr>
-    <td><dfn>ontransitionend</dfn></td>
+    <td>{{GlobalEventHandlers/ontransitionend}}</td>
     <td><a idl>transitionend</a></td>
   </tr>
   <tr>
-    <td><dfn>ontransitioncancel</dfn></td>
+    <td>{{GlobalEventHandlers/ontransitioncancel}}</td>
     <td><a idl>transitioncancel</a></td>
   </tr>
 </table>