code: public static JMenu leftShift(JMenu self, Action action) {
          self.add(action);
          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 action an action to be added to the menu.
  @return same menu, after the value was added to it.
  @since 1.6.4