Method relocate

include/boost/json/value.hpp:3179–3189

private:
    static
    void
    relocate(
        value* dest,
        value const& src) noexcept
    {
        std::memcpy(
            static_cast<void*>(dest),
            &src,
            sizeof(src));
    }

    BOOST_JSON_DECL
    storage_ptr