Method get_token_string

lesson6-Segmentation/json.hpp:10037–10042

! @return a string representation of the last read byte */

    @return a string representation of the last read byte
    */
    std::string get_token_string() const
    {
        std::array<char, 3> cr{{}};
        (std::snprintf)(cr.data(), cr.size(), "%.2hhX", static_cast<unsigned char>(current));
        return std::string{cr.data()};
    }

    /*!
    @param[in] format   the current format