18.2.1

• bn::forward_list and bn::intrusive_forward_list forward iterator requirements fixed.
• bn::list, bn::intrusive_list, bn::unordered_map and bn::unordered_set bidirectional iterator requirements fixed.
• bn::deque random access iterator requirements fixed.
• bn::deque, bn::list, bn::intrusive_list, bn::forward_list, bn::intrusive_forward_list, bn::unordered_map and bn::unordered_set iterator type aliases fixed.