Correct type inference for UInt64Index during access
- [x] closes #28023 and closes #28279
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Thanks for the PR! Test failures related to https://github.com/pandas-dev/pandas/issues/29432 Hello @oguzhanogreden! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:





There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2019-11-23 15:22:46 UTC This will fail due to #29526. Between two laptops and a rebase, git happened again. Sorry for the spam! @jschendel [here](https://github.com/pandas-dev/pandas/pull/29529#pullrequestreview-314688566) you suggested that the What's New entry goes under `Numeric`. It's not clear to me why these are not under `Indexing`. Can you confirm that this is where the last 4 entries do belong? The "Indexing" section is generally for operations that have to do with selecting data with an index, e.g. `loc`/`iloc`, and the associated index methods that support this, e.g. `get_loc`/`get_indexer`. For example, see the types of things tested in `pandas/tests/indexing`.  The "Numeric" section deals more with issues related to numeric operations, e.g. computation, precision, inference, etc. thanks for the patch @oguzhanogreden 