Feature request

As of PHP 8.1.0, a class which implements Serializable without also implementing __serialize() and __unserialize() will generate a deprecation warning.

see

• https://www.php.net/manual/en/class.serializable.php
• https://3v4l.org/JotHY

I think phpstan should emit a similar error, as it doesn't right now:
https://phpstan.org/r/c1d859f3-08f0-47f6-9771-ee60d771ea2a