Make it possible to forward declare wx{Choice,Tool,Tree}bookEvent again.

Don't use typedef for these classes as it makes it impossible to
forward-declare them, just use #define instead as we already do for
wxListbookEvent and wxNotebookEvent. This allows forward declaration and is
also more consistent.

Closes #12242.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71310 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/choicebk.h

@@ -111,7 +111,7 @@ private:
 // ----------------------------------------------------------------------------
 
 // wxChoicebookEvent is obsolete and defined for compatibility only
-typedef wxBookCtrlEvent wxChoicebookEvent;
+#define wxChoicebookEvent wxBookCtrlEvent
 typedef wxBookCtrlEventFunction wxChoicebookEventFunction;
 #define wxChoicebookEventHandler(func) wxBookCtrlEventHandler(func)
 

include/wx/toolbook.h

@@ -128,7 +128,7 @@ private:
 // ----------------------------------------------------------------------------
 
 // wxToolbookEvent is obsolete and defined for compatibility only
-typedef wxBookCtrlEvent wxToolbookEvent;
+#define wxToolbookEvent wxBookCtrlEvent
 typedef wxBookCtrlEventFunction wxToolbookEventFunction;
 #define wxToolbookEventHandler(func) wxBookCtrlEventHandler(func)
 

include/wx/treebook.h

@@ -229,7 +229,7 @@ private:
 // ----------------------------------------------------------------------------
 
 // wxTreebookEvent is obsolete and defined for compatibility only
-typedef wxBookCtrlEvent wxTreebookEvent;
+#define wxTreebookEvent wxBookCtrlEvent
 typedef wxBookCtrlEventFunction wxTreebookEventFunction;
 #define wxTreebookEventHandler(func) wxBookCtrlEventHandler(func)