Fix relationship.order_by typing

Fix relationship.order_by typing

Fixes: #8776
### Checklist

This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

Closes: #8779
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/8779
Pull-request-sha: 2bc64555a1ab662881fdfd1caaabd9d21fbdf531

Change-Id: I52fe6db5ba954a6039836b45f0e89ad96049df03