function createAlwaysStylePattern(markers, exceptions) {
	let pattern = "^";

	/*
	 * A marker or nothing.
	 * ["*"]            ==> "\*?"
	 * ["*", "!"]       ==> "(?:\*|!)?"
	 * ["*", "/", "!<"] ==> "(?:\*|\/|(?:!<))?" ==> https://jex.im/regulex/#!embed=false&flags=&re=(%3F%3A%5C*%7C%5C%2F%7C(%3F%3A!%3C))%3F
	 */
	if (markers.length === 1) {
		// the marker.
		pattern += escape(markers[0]);
	} else {
		// one of markers.
		pattern += "(?:";
		pattern += markers.map(escape).join("|");
		pattern += ")";
	}

	pattern += "?"; // or nothing.
	pattern += createExceptionsPattern(exceptions);

	return new RegExp(pattern, "u");
}
Creates RegExp object for `always` mode.
Generated pattern for beginning of comment:

1. First, a marker or nothing.
2. Next, a space or an exception pattern sequence.
@param {string[]} markers A marker list.
@param {string[]} exceptions An exception pattern list.
@returns {RegExp} A RegExp object for the beginning of a comment in `always` mode.