Fix PR08 errors
Fixes PR08 errors. When I ran the script, a lot of them seem to be false positives, these are the ones I'm pretty sure should be fixed:
```
pandas.infer_freq: Parameter "index" description should start with a capital letter
pandas.MultiIndex.get_loc_level: Parameter "drop_level" description should start with a capital letter
```
Related to #27977 cc @datapythonista

- [ ] closes #xxxx
- [ ] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
