doc: use Object.hasOwn() in util doc

Swtich from `hasOwnProperty()` to `Object.hasOwn()`.

doc/api/util.md

@@ -67,7 +67,7 @@ const callbackFunction = util.callbackify(fn);
 callbackFunction((err, ret) => {
   // When the Promise was rejected with `null` it is wrapped with an Error and
   // the original value is stored in `reason`.
-  err && err.hasOwnProperty('reason') && err.reason === null;  // true
+  err && Object.hasOwn(err, 'reason') && err.reason === null;  // true
 });
 ```