fix push/pop mechanism after r58786; add a few notes about the stack mechanism both in the docs and in the public header (see #10733)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60321 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/statusbr.h

@@ -105,6 +105,8 @@ public:
     // field text
     // ----------
 
+    // NOTE: even if it is not pure virtual, SetStatusText() must be overloaded by 
+    //       the derived classes to update the given text in the native control
     virtual void SetStatusText(const wxString& text, int number = 0)
         { m_panes[number].GetStack().Last() = text; }
     virtual wxString GetStatusText(int number = 0) const