Smart completion: generic functions are correctly included into the list

#KT-6375 Fixed

idea/testData/completion/smart/GroupBySubstitutor.kt

@@ -0,0 +1,14 @@
+fun<T> emptyList(): List<T> = listOf()
+
+fun foo(list: List<String>){}
+fun foo(list: List<String>, i: Int){}
+fun foo(list: List<Int>, b: Boolean){}
+fun foo(list: List<Int>, c: Char){}
+
+fun f(){
+    foo(empty<caret>)
+}
+
+// EXIST: { lookupString: "emptyList", typeText: "List<String>" }
+// EXIST: { lookupString: "emptyList", typeText: "List<Int>" }
+// NUMBER: 2