Return wxPrintAbortDialog from CreateAbortWindow().

Instead of returning a generic wxWindow*, return the type actually used.
It was part of the public header already, but not used in any publicly
visible way.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72306 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/print.h

@@ -465,7 +465,7 @@ public:
     /**
         Creates the default printing abort window, with a cancel button.
     */
-    virtual wxWindow* CreateAbortWindow(wxWindow* parent, wxPrintout* printout);
+    virtual wxPrintAbortDialog* CreateAbortWindow(wxWindow* parent, wxPrintout* printout);
 
     /**
         Returns @true if the user has aborted the print job.