update/reorganize events overview and changed links to it to reflect the fact that it speaks about events in general and not just about handling them

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58712 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/bookctrl.h

@@ -168,7 +168,7 @@ public:
         This function behaves as SetSelection() but does @em not generate the
         page changing events.
 
-        See @ref overview_eventhandling_prog for more information.
+        See @ref overview_events_prog for more information.
     */
     virtual int ChangeSelection(size_t page) = 0;