DOC add example to reorder levels
Response to changes suggested on my previous pull request

- [x] closes #42124
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Hello @trevorkask! 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 2021-08-23 15:16:42 UTC Are you going to close #42667 or this? You should really continue that PR and close this one. use this one Thanks @trevorkask 