[html-aam] Set heading level based on HTML computed heading level

Author: keithamus

html-aam/index.html

@@ -2659,8 +2659,7 @@ <h4 id="el-h1-h6">`h1`, `h2`, `h3`, `h4`, `h5`, and `h6`</h4>
             <tr>
               <th>[[wai-aria-1.2]]</th>
               <td>
-                <a class="core-mapping" href="#role-map-heading">`heading`</a> role, with the <a class="core-mapping" href="#ariaLevel">`aria-level`</a> property set to the number in the element's tag
-                name.
+                <a class="core-mapping" href="#role-map-heading">`heading`</a> role, with the <a class="core-mapping" href="#ariaLevel">`aria-level`</a> property set to the <a data-cite="html/sections.html#get-an-element's-computed-heading-offset">the computed heading level</a>.
               </td>
             </tr>
             <tr>