added explanation

rowers/templates/summary_edit.html

@@ -60,7 +60,9 @@
       </tr>
     </table>
 		<h1>Feeling lucky?</h1>
-		<p>
+		<p>This new, experimental feature tries to find intervals by looking for patterns in the data. It does not
+			autodetect rest and work intervals yet. The resulting "interval string" is copied to the Interval Shorthand
+			section below, where you can edit it.
 			<form enctype="multipart/form-data" method="post">
 				<input type="hidden" name="ruptures" value="ruptures">
 				<table width=100%>