TYP: Added typing to __eq__ functions
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

> Should `other` always be typed as `Any`?

looking at typeshed, probably should be typed as `object`.

Using anything other than `object` (or `Any`) will report ` error: Argument 1 of "__eq__" incompatible with supertype "object"`, see https://stackoverflow.com/questions/37557411/why-does-defining-the-argument-types-for-eq-throw-a-mypy-type-error The tests failed exactly where it failed [here](https://github.com/pandas-dev/pandas/pull/29844) which it should not fail there, all that was changed was the ```README.md``` file. is it possible that it's a false positive? thanks @MomIsBestFriend 