<!--
Thank you for contributing to Ruff! To help us out with reviewing,
please consider the following:
- Does this pull request include a summary of the change? (See below.)
- Does this pull request include a descriptive title?
- Does this pull request include references to any relevant issues?
-->
## Summary
Resolves#12636
Consider docstrings which begin with the word "Returns" as having
satisfactorily documented they're returns. For example
```python
def f():
"""Returns 1."""
return 1
```
is valid.
## Test Plan
Added example to test fixture.
---------
Co-authored-by: Dhruv Manilawala <dhruvmanila@gmail.com>
Tom Kuson
Auguste Lalande