generateHeader(module, requestShortener) {
		const req = module.readableIdentifier(requestShortener);
		const reqStr = req.replace(/\*\//g, "*_/");
		const reqStrStar = "*".repeat(reqStr.length);
		const headerStr = `/*!****${reqStrStar}****!*\\\n  !*** ${reqStr} ***!\n  \\****${reqStrStar}****/\n`;
		return new RawSource(headerStr);
	}
@param {Module} module the module
@param {RequestShortener} requestShortener request shortener
@returns {RawSource} the header