Function reset

include/jwt/json/json.hpp:7191–7196

reset token_buffer; current character is beginning of token

    /// reset token_buffer; current character is beginning of token
    void reset() noexcept
    {
        token_buffer.clear();
        token_string.clear();
        token_string.push_back(std::char_traits<char_type>::to_char_type(current));
    }

    /*
    @brief get next character from the input