Add clarification

index.html

@@ -290,7 +290,7 @@ <h4>Game streaming</h4>
            <td>N37</td>
            <td>It must be possible for the user agent's receive pipeline to process
            video at high resolution and framerate (e.g. by controlling hardware
-	   acceleration).</td>
+	   acceleration if necessary).</td>
         </tr>
         <tr>
            <td>N38</td>