Mark XMLDocument::validate() no longer as tentative-return-type

Author: nielsdos

ext/dom/php_dom.stub.php

@@ -1197,7 +1197,6 @@ public static function createFromString(string $source, int $options = 0, ?strin
         public function createEntityReference(string $name) {}
 
         /**
-         * @tentative-return-type
          * @implementation-alias DOMDocument::validate
          */
         public function validate(): bool {}