Remove aria-level attribute from listitem (#1484)

Author: WilliamTennisNFCU

index.html

@@ -4747,7 +4747,6 @@ <h5>Note regarding the ARIA 1.3 <code>image</code> role.</h5>
 						<th class="role-properties-head" scope="row">Supported States and Properties:</th>
 						<td class="role-properties">
 							<ul>
-								<li><pref>aria-level</pref></li>
 								<li><pref>aria-posinset</pref></li>
 								<li><pref>aria-setsize</pref></li>
 							</ul>