Function operator--

Source/external/json.hpp:13203–13208

! @brief post-decrement (it--) @pre The iterator is initialized; i.e. `m_object != nullptr`. */

	@pre The iterator is initialized; i.e. `m_object != nullptr`.
	*/
	iter_impl operator--(int)& // NOLINT(cert-dcl21-cpp)
	{
		auto result = *this;
		--(*this);
		return result;
	}

	/*!
	@brief pre-decrement (--it)