Add never used AddCoversClassAttributeRector

do you have some stats for rules? I don't know if others are using it, but we do use it in Infection and we (as a mutation testing library) highly promote the usage of #[CoversClass] that this rule helps to achieve.

So not sure why it was removed.

Thanks for reaching out. We collect info from issue report, number of active sets, use on Github except forks etc.
https://github.com/search?q=AddCoversClassAttributeRector%3A%3Aclass&type=code
But there is more context.

I'm going through rules that are never used/mentioned in PR/issues/sets to narrow down core to more generic ones, that 80 %+ users would benefit from. These onezie rules are often experiments, or custom rules that we accepted in core to try out. This one is used just once, works with paths and all-class reflections.

That's why it's better fit as a custom rule, not in core. Move it to /utils in your project to keep using it.