Function emplace

include/behaviortree_cpp/contrib/json.hpp:19058–19069

        : Container{init, alloc} {}

    std::pair<iterator, bool> emplace(const key_type& key, T&& t)
    {
        for (auto it = this->begin(); it != this->end(); ++it)
        {
            if (m_compare(it->first, key))
            {
                return {it, false};
            }
        }
        Container::emplace_back(key, std::forward<T>(t));
        return {std::prev(this->end()), true};
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>