Correct alignment of menu accelerator strings in owner-drawn menus.

Draw them right-aligned as the native menus do.

Closes #11479.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63224 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/menuitem.h

@@ -107,6 +107,7 @@ public:
     const wxBitmap& GetDisabledBitmap() const
         { return m_bmpDisabled; }
 
+    int MeasureAccelWidth() const;
 
     // override wxOwnerDrawn base class virtuals
     virtual wxString GetName() const;