FE: provide argument mapping info for adapted callable reference

compiler/psi/src/org/jetbrains/kotlin/psi/ValueArgument.kt

@@ -36,6 +36,10 @@ interface ValueArgument {
     fun isExternal(): Boolean
 }
 
+interface FakePositionalValueArgumentForCallableReference : ValueArgument {
+    val index: Int
+}
+
 interface LambdaArgument : ValueArgument {
     fun getLambdaExpression(): KtLambdaExpression?
 }