Fix repl tests

Author: szymon-rd

compiler/test-resources/repl/rewrite-messages

@@ -1,17 +1,20 @@
 //> using options -source:future-migration -deprecation -Werror
 scala> import scala.util._
--- Error: ----------------------------------------------------------------------
+-- Migration Warning: ----------------------------------------------------------
 1 | import scala.util._
   |                   ^
   |         `_` is no longer supported for a wildcard import; use `*` instead
-
+No warnings can be incurred under -Werror.
+1 warning found
+1 error found
 scala> extension (x: Int) def foo(y: Int) = x + y
 def foo(x: Int)(y: Int): Int
-
 scala> 2 foo 4
--- Error: ----------------------------------------------------------------------
+-- Migration Warning: ----------------------------------------------------------
 1 | 2 foo 4
   |   ^^^
   |Alphanumeric method foo is not declared infix; it should not be used as infix operator.
   |Instead, use method syntax .foo(...) or backticked identifier `foo`.
-1 error found
+No warnings can be incurred under -Werror.
+1 warning found
+1 error found