Since request #43700, we can use PHP 8.3 syntax like the Override attribute.

We should mark recently-introduced overriding methods with this attribute, so that it is clear that the end-of-chain method is actually overriding a parent method. PHP will also raise an error if we delete the parent method, which will warn developers that they must use caution.

Psalm can also flag missing attributes. Leveraging this, we should enable this setting and commit existing lack of attributes to the baseline. We can then add missing attributes slowly over time when we touch things dealing with inheritance. New usages should apply the override attribute as part of the normal work, not as a separate request.