Function rbegin

lesson6-Segmentation/json.hpp:21107–21110

! @brief returns an iterator to the reverse-beginning Returns an iterator to the reverse-beginning; that is, the last element. @image html range-rbegin-rend.svg "Illustration from cppreference.com" @complexity Constant. @requirement This function helps `basic_json` satisfying the [ReversibleContainer](https://en.cppreference.com/w/cpp/named_req/ReversibleContainer)

    @since version 1.0.0
    */
    reverse_iterator rbegin() noexcept
    {
        return reverse_iterator(end());
    }

    /*!
    @copydoc basic_json::crbegin()