BUG: column names with degree sign make query fail
This pull request adds DEGREESIGN (°) to tokens that are parsed and escaped in a backticked column. There are no separate issue reporting this, but this is similar to the EUROSIGN issue previously addressed.

- [ ] closes #xxxx
- [x] tests added / passed
- [ ] 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
