Method SkipUtf8If

src/core/string_consumer.hpp:511–517

* If the next data matches the UTF-8 char 'c', then skip it. */

	 * If the next data matches the UTF-8 char 'c', then skip it.
	 */
	void SkipUtf8If(char32_t c)
	{
		auto [len, result] = this->PeekUtf8();
		if (len > 0 && result == c) {
			this->Skip(len);
		}
	}

	/**
	 * Peek the next 'len' bytes.