Merge pull request #309 from carmacleod/issue308

Remove confusion in h1 to h6 implied mapping wording

Author: patrickhlauke

index.html

@@ -1024,7 +1024,7 @@ <h2 id="docconformance">
             </th>
             <td>
               <code>role=<a href="#index-aria-heading">heading</a></code>,
-              with the `aria-level` = positive integer.
+              `aria-level` = the number in the element's tag name.
             </td>
             <td>
               <p>