ENH: RangeIndex.sort_values now avoids materialization of values
- [x] closes #43584
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [x] whatsnew entry
What's new: On any instance of RangeIndex, sort_values will not sort as it is already sorted.
also pls add asv's that catch this case. also some pre-commit issues with typing: https://github.com/pandas-dev/pandas/pull/43666/checks?check_run_id=3659974388 @usersblock if you can address comments and merge master I still need to know whether I should remove the @final since it's blocking my override.
 > I still need to know whether I should remove the @Final since it's blocking my override.

yes you should Hello @usersblock! 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 2021-10-19 22:06:41 UTC cc @jbrockmendel if comments i think in test_algos.TestFactorize.test_factorize with this PR you could pass `exact=True` to `assert_index_equal` thanks @usersblock very nice!