Make wxDumpWindow() take const wxWindow pointer

There is no reason not to allow calling this function with const window,
so do allow it, notably to make it possible to use it with "this" from
const wxWindow methods.

include/wx/window.h

@@ -2148,7 +2148,7 @@ extern WXDLLIMPEXP_CORE wxWindow *wxGetActiveWindow();
 WXDLLIMPEXP_CORE wxWindow* wxGetTopLevelParent(wxWindowBase *win);
 
 // Return a string with platform-dependent description of the window.
-extern WXDLLIMPEXP_CORE wxString wxDumpWindow(wxWindowBase* win);
+extern WXDLLIMPEXP_CORE wxString wxDumpWindow(const wxWindowBase* win);
 
 #if wxUSE_ACCESSIBILITY
 // ----------------------------------------------------------------------------

interface/wx/window.h

@@ -4364,7 +4364,7 @@ wxWindow* wxGetTopLevelParent(wxWindow* window);
 
     @since 3.1.6
  */
-wxString wxDumpWindow(wxWindow* window);
+wxString wxDumpWindow(const wxWindow* window);
 
 //@}
 

src/common/wincmn.cpp

@@ -3722,7 +3722,7 @@ wxWindow* wxGetTopLevelParent(wxWindowBase *win_)
     return win;
 }
 
-wxString wxDumpWindow(wxWindowBase* win)
+wxString wxDumpWindow(const wxWindowBase* win)
 {
     if ( !win )
         return wxString::FromAscii("[no window]");