Allow top-level `await` in Jupyter notebooks (#6607)
## Summary
Top-level `await` is allowed in Jupyter notebooks (see:
[autoawait](https://ipython.readthedocs.io/en/stable/interactive/autoawait.html)).
Closes https://github.com/astral-sh/ruff/issues/6584.
## Test Plan
Had to test this manually. Created a notebook, verified that the `yield`
was flagged but the `await` was not.
<img width="868" alt="Screen Shot 2023-08-15 at 11 40 19 PM"
src="https://github.com/astral-sh/ruff/assets/1309177/b2853651-30a6-4dc6-851c-9fe7f694b8e8">
