Method insert_or_assign

include/tsl/ordered_map.h:273–275

  template <class M>
  std::pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj) {
    return m_ht.insert_or_assign(k, std::forward<M>(obj));
  }

  template <class M>
  std::pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj) {