Pass subtype to "create an input source"

Author: yezhizhen

index.html

@@ -8197,7 +8197,7 @@ <h3>Input state</h3>
 
   <li><p>If <var>source</var> is undefined, set <var>source</var> to
   the result of <a>trying</a> to <a>create an input source</a>
-  with <var>input state</var> and <var>type</var>.
+  with <var>input state</var>, <var>type</var> and <var>subtype</var>.
 
  <li><p>Return success with data <var>source</var>.</p></li>
 </ol>