[flake8-simplify] Omit select context managers from SIM117

[maltevesper]

Semantically it makes sense to put certain contextmanagers into separate with statements. Currently asyncio.timeout and its relatives in anyio and trio are exempt from SIM117.

Closes #8606

Summary

Exempt asyncio.timeout and related functions from SIM117 (Collapse with statements where possible).
See #8606 for more.

Test Plan

Extended the insta tests.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[maltevesper]

I have not figured out how to make ruff work if the context manager is assigned to a variable.

x = asyncio.timeout(1)
async with x:
     async with A():
          ...

A quick poke around revealed that x is a binding, but I did not see how to extract type information for x, given that ruff is a linter/formatter and not a typechecker I assume this functionality is currently not included.
Should I bee mistaken, this PR would need fixing up.

[charliermarsh]

Thank you!