code: public static JMenu leftShift(JMenu self, GString gstr) {
          self.add(gstr.toString());
          return self;
      }
docs: Overloads the left shift operator to provide an easy way to add
  components to a menu.<p>
  
  @param self a JMenu
  @param gstr a GString to be added to the menu.
  @return same menu, after the value was added to it.
  @since 1.6.4