Function _isHexDigit

lib/css/syntax.js:310–313

(cc)

 * @returns {boolean} true, if cc is a hex digit
 */
const _isHexDigit = (cc) =>
	_isDigit(cc) ||
	(cc >= CC_UPPER_A && cc <= CC_UPPER_F) ||
	(cc >= CC_LOWER_A && cc <= CC_LOWER_F);

/**
 * @param {number} cc char code