Function repeat

include/boost/parser/parser.hpp:6616–6619

        given parser of type `parser_interface<P>`. */
    template<typename T>
    constexpr repeat_directive<T, T> repeat(T n) noexcept
    {
        return repeat_directive<T, T>{n, n};
    }

    /** Returns a `repeat_directive` that repeats exactly `n` times, where the
        items parsed are delimited by `DelimiterParser`.  The value returned