(editorial) remove confusing "(see structure)" from menuitemradio sup…

…erclass (#1145)

index.html

@@ -5559,7 +5559,7 @@ <h4>Plain HTML or Polyfill DOM Result of the MathML Quadratic Formula</h4>
 						<th class="role-parent-head" scope="row">Superclass Role:</th>
 						<td class="role-parent">
 							<ul>
-								<li><rref>menuitemcheckbox</rref> (see structure)</li>
+								<li><rref>menuitemcheckbox</rref></li>
 								<li><rref>radio</rref></li>
 							</ul>
 						</td>