Declare various WXH* handles compatibly with SDK.

It is no longer necessary to cast between e.g. HINSTANCE and
WXHINSTANCE, they are now declared as the same type (without including
Windows SDK header).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64138 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/toolbar.cpp

@@ -1807,7 +1807,7 @@ WXHBRUSH wxToolBar::MSWGetToolbarBgBrush()
     wxBrush * const
         brush = wxTheBrushList->FindOrCreateBrush(colBg);
 
-    return brush ? brush->GetResourceHandle() : 0;
+    return brush ? static_cast<WXHBRUSH>(brush->GetResourceHandle()) : 0;
 }
 
 WXHBRUSH wxToolBar::MSWGetBgBrushForChild(WXHDC hDC, wxWindowMSW *child)