Fix type tests (#51558)

Author: stayallive

types/Support/Helpers.php

@@ -42,7 +42,7 @@
     return 10;
 }));
 
-assertType('mixed', with(new User(), function ($user) {
+assertType('User', with(new User(), function ($user) {
     return $user;
 }));
 assertType('User', with(new User(), function ($user): User {