fixed required=required documentation

validator/index.html

@@ -201,7 +201,7 @@ <h3>HTML5 Attributes</h3>
 		<td class="code">required</td>
 		<td><code>"required"</code></td>
 		<td>
-			Makes value submission mandatory for this field. The standard syntax is <samp>required="required"</samp>, but this tool allows you to write <samp>required="true"</samp> or simply <samp>required</samp>. Works with checkbox and SELECT fields too. 
+			Makes value submission mandatory for this field. The standard syntax is <samp>required="required"</samp> is needed! Plain <samp>required</samp> or <samp>required="true"</samp> does not work. This attribute works also with checkbox and SELECT fields. 
 		</td>
 	</tr>
 </table>