code: def reverse_each_item
        return to_enum(__method__) { count } unless block_given?
        return if empty?
  
        item = list_tail
        loop do
          yield item
          item = item.prev
        end
      end
docs: Iterates over each item in the list in reverse order. If a block is not
   given an enumerator is returned.
  
   @yield  [Listable] each item in the list.
   @return [Enumerable] if no block is given.