Document wxHtmlCellEvent::GetMouseEvent()

Closes https://github.com/wxWidgets/wxWidgets/pull/1195

interface/wx/html/htmlwin.h

@@ -621,6 +621,11 @@ public:
     */
     wxPoint GetPoint() const;
 
+    /**
+        Returns the wxMouseEvent associated with the event.
+    */
+    wxMouseEvent GetMouseEvent() const;
+
     /**
         Call this function with @a linkclicked set to @true if the cell which has
         been clicked contained a link or @false otherwise (which is the default).