Remove redundant return from parsers.blockRuleset()

Author: Krinkle

packages/less/src/less/parser/parser.js

@@ -1478,11 +1478,9 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
 
             blockRuleset: function() {
                 let block = this.block();
-
                 if (block) {
-                    block = new tree.Ruleset(null, block);
+                    return new tree.Ruleset(null, block);
                 }
-                return block;
             },
 
             detachedRuleset: function() {
@@ -2491,4 +2489,4 @@ Parser.serializeVars = vars => {
     return s;
 };
 
-export default Parser;
+export default Parser;