fix rule placement for scalafix test

Author: jrudolph

http-scalafix/scalafix-test-input/src/main/scala/org/apache/pekko/http/fix/MigrateToServerBuilderTest.scala

@@ -1,3 +1,7 @@
+/*
+rule = MigrateToServerBuilder # This has to be at the top
+ */
+
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * license agreements; and to You under the Apache License, version 2.0:
@@ -7,10 +11,6 @@
  * This file is part of the Apache Pekko project, which was derived from Akka.
  */
 
-/*
-rule = MigrateToServerBuilder
- */
-
 package org.apache.pekko.http.fix
 
 import org.apache.pekko