fix psalm

Author: michalsn

tests/system/Entity/EntityTest.php

@@ -2368,6 +2368,9 @@ public function testHasChangedPrefersToArrayOverTraversable(): void
             ];
         };
 
+        /**
+         * @extends ArrayObject<string, string>
+         */
         $items = new class (['iterator' => 'original']) extends ArrayObject {
             /**
              * @return array<string, string>