removed unneeded parameter

lib/single-file/rules-matcher.js

@@ -118,7 +118,7 @@ this.RulesMatcher = this.RulesMatcher || (() => {
 	}
 
 	function computeCascade(mediaInfo, parentMediaInfos, allMediaInfo) {
-		mediaInfo.elements.forEach((elementInfo, element) => {
+		mediaInfo.elements.forEach(elementInfo => {
 			getStylesInfo(elementInfo).forEach((elementStyleInfo, styleName) => {
 				let ruleInfo, ascendantMedia;
 				if (elementStyleInfo.cssRule) {