KT-1633 support completion of named function parameters

idea/testData/completion/basic/common/namedParameters/NoAlreadyUsedParameters.kt

@@ -0,0 +1,11 @@
+fun foo(paramFirst: String, paramSecond: String, paramThird: String, paramFourth: String) {}
+
+fun test() {
+    foo("str", paramThird = "test", param<caret>)
+}
+
+// ABSENT: paramFirst
+// EXIST: paramSecond
+// ABSENT: paramThird
+// EXIST: paramFourth
+