Fix test

Author: odersky

tests/pos/capturing.scala

@@ -1,7 +1,7 @@
 object Test:
 
   extension [A <: Any retains *] (xs: LazyList[A])
-    def lazyMap[B <: Any retains *] (f: A => B retains *): LazyList[B] retains f.type | A | B =
+    def lazyMap[B <: Any retains *] (f: (A => B) retains *): LazyList[B] retains f.type | A | B =
       val x: Int retains f.type | A = ???
       val y = x
       val z: Int retains A retains f.type = y