adding wxFALLTHROUGH where until now we had comments, allows for code-analysis support

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76399 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/treebase.cpp

@@ -359,7 +359,7 @@ void wxTreeCtrlBase::OnCharHook(wxKeyEvent& event)
         {
             case WXK_ESCAPE:
                 discardChanges = true;
-                // fall through
+                wxFALLTHROUGH;
 
             case WXK_RETURN:
                 EndEditLabel(GetFocusedItem(), discardChanges);