Slightly simplify the previous commits

Remove SetWindowMenuLabelTranslated() which was only called once and so
didn't seem to be worth having. Also get rid of WINDOW_MENU_LABEL for
the same reason: it was used only once and imposed the use of
gettext_noop() which is not needed any longer.

Rename GetWindowMenuLabelTranslated() to have a MSW prefix in order to
indicate that it's a private MSW function and not part of the public wx
API.

Also renamed "Translated" to "Current" to (hopefully) more clearly
indicate why do we need to keep this variable.

include/wx/msw/mdi.h

@@ -85,11 +85,12 @@ public:
     virtual void RemoveMDIChild(wxMDIChildFrame *child);
 #endif // wxUSE_MENUS
 
-    // called by AddWindowMenu to remember the translation of the window menu label
-    void SetWindowMenuLabelTranslated();
-
-    // called by AddWindowMenu and RemoveWindowMenu to get the last used translation of the window menu label
-    const wxString GetWindowMenuLabelTranslated() const;
+    // Retrieve the current window menu label: it can be different from
+    // "Window" when using non-English translations and can also be different
+    // from wxGetTranslation("Window") if the locale has changed since the
+    // "Window" menu was added.
+    const wxString& MSWGetCurrentWindowMenuLabel() const
+        { return m_currentWindowMenuLabel; }
 
     // handlers
     // --------
@@ -157,7 +158,7 @@ private:
     bool m_activationNotHandled;
 
     // holds the current translation for the window menu label
-    wxString m_windowMenuLabelTranslated;
+    wxString m_currentWindowMenuLabel;
 
 
     friend class WXDLLIMPEXP_FWD_CORE wxMDIChildFrame;