Fix missing newline at end of test

Author: Sporarum

tests/pos/i14451.scala

@@ -24,4 +24,4 @@ val v3 = (new Foo).f3
 extension [A](dfVal: Foo)
   def f4[T](step: Int): Foo = ???
   def f4[T]: Foo = ???
-val v4 = (new Foo).f4
+val v4 = (new Foo).f4