complex_example.html: Now we can guess more easily that checkbox are options

examples/complex_example.html

@@ -101,6 +101,7 @@ var clearlog = function () {
     </tr>
     <tr>
       <td colspan="2" style="text-align: center;">
+        Options:<br />
         <label for="prev_rev">Previous revision:</label>
         <input type="text" id="prev_rev" value="" style="width: 40em;"/><br />
         <label for="show_conflicts">Show Conflicts</label>