Added more explanation for WLeafletMap to release notes

overview.html

@@ -57,7 +57,9 @@ <h3>Notable backwards-incompatible changes</h3>
 </ul>
 <h3>New widgets</h3>
 <ul>
-  <li><b><a href="eu/webtoolkit/jwt/WLeafletMap.html">WLeafletMap</a></b>: this is a wrapper around the <a href="https://leafletjs.com/" target="_blank">Leaflet</a> JavaScript library.</li>
+  <li>
+    <a href="eu/webtoolkit/jwt/WLeafletMap.html">WLeafletMap</a>: this is a wrapper around the <a href="https://leafletjs.com/" target="_blank">Leaflet</a> JavaScript library. It has support for some basic features of Leaflet, and one special feature: the ability to add arbitrary widgets (within reason) as markers to the map using <a href="eu/webtoolkit/jwt/WLeafletMap.WidgetMarker.html">WidgetMarker</a>.
+  </li>
 </ul>
 <h3>New examples</h3>
 <ul>