Update the test to actually test what we intended

tests/cases/fourslash/completionListNewIdentifierVariableDeclaration.ts

@@ -1,6 +1,6 @@
 /// <reference path='fourslash.ts' />
 
-////var x : (/*1*/) => void;
+////var x : (s/*1*/
 
 ////var y : (s:string, list/*2*/