Rename file, add to understanding doc.

Author: alastc

techniques/failures/failure-downevent-not-upevent-no-mitigating-circumstances.html renamed to techniques/failures/F101.html

@@ -87,7 +87,7 @@ <h2>Advisory</h2>
 			<section id="failure">
 				<h2>Failure</h2>
 				<ul>
-					<li>@@  Failure of SC 2.5.3 due to activating a button on initial touch location rather than the final touch location.</li>      
+					<li><a href="../../techniques/failures/F101">Failure of Success Criterion 2.5.2 due to activating a control on the down-event</a></li>      
 				</ul>
 			</section>
 		</section>