Adding back events documentation.

When the list of event types became unconstrained in 501b42228a, we lost the documentation for events that are triggered.  This change adds the list of events triggered to the API docs for events properties.

lib/OpenLayers/Control/WMSGetFeatureInfo.js

@@ -154,8 +154,17 @@ OpenLayers.Control.WMSGetFeatureInfo = OpenLayers.Class(OpenLayers.Control, {
      */
     hoverRequest: null,
     
-    /**
-     * Supported event types (in addition to those from <OpenLayers.Control>):
+    /** 
+     * APIProperty: events
+     * {<OpenLayers.Events>} Events instance for listeners and triggering
+     *     control specific events.
+     *
+     * Register a listener for a particular event with the following syntax:
+     * (code)
+     * control.events.register(type, obj, listener);
+     * (end)
+     *
+     * Supported event types (in addition to those from <OpenLayers.Control.events>):
      * beforegetfeatureinfo - Triggered before the request is sent.
      *      The event object has an *xy* property with the position of the 
      *      mouse click or hover event that triggers the request.