[`pylint`] Implement `unnecessary-dunder-call` (`C2801`) (#9166)
## Summary
Implements
[`C2801`/`unnecessary-dunder-calls`](https://pylint.readthedocs.io/en/stable/user_guide/messages/convention/unnecessary-dunder-call.html)
There are more that this could cover, but the implementations get a
little less straightforward and ugly. Might come back to it in a future
PR, or someone else can!
See: #970
## Test Plan
`cargo test`
