DOC: Add DataFrame.index.levels
- [X] xref #55435
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

Add docstrings for MultiIndex.levels and MultiIndex.codes


/preview Website preview of this PR available at: https://pandas.pydata.org/preview/55437/ Looks like something is broken in the last part of the examples, you can see it here: https://pandas.pydata.org/preview/55437/docs/reference/api/pandas.MultiIndex.levels.html#pandas.MultiIndex.levels

Can you have a look please? > Amazing work @shiersansi, thanks a lot for working on this!

Thank you for your help and advice. Your help has made me understand more about how to contribute to open source projects, and I have learned a lot through this docstring modification > > Amazing work @shiersansi, thanks a lot for working on this!
> 
> Thank you for your help and advice. Your help has made me understand more about how to contribute to open source projects, and I have learned a lot through this docstring modification

Amazing, I'm glad to hear. Feel free to continue working in other things, and please let me know if you need help. For this PR we'll wait until the CI finishes, and another core developer has time to review it, in case I missed something, but it should be ready from your side. Thanks @shiersansi 