KT-4909 Smart completion does not work for named arguments

KT-7668 Named argument completion does not work after vararg

 #KT-4909 Fixed
 #KT-7668 Fixed

idea/idea-completion/testData/basic/common/namedParameters/AfterVararg.kt

@@ -0,0 +1,7 @@
+fun foo(vararg strings: String, option: String = ""){ }
+
+fun bar(s: String){
+    foo("", "", <caret>)
+}
+
+// EXIST: { lookupString:"option", itemText:"option =" }