[flake8-bugbear] Improve assert-raises-exception (B017) message

[tjkuson]

Summary

Changes the assert-raises-exception (B017) message to be more helpful. In doing so, the message is shorter and the implementation simpler as the diagnostic no longer needs to print the assertion.

- B017.py:45:10: B017 `pytest.raises(Exception)` should be considered evil
+ B017.py:45:10: B017 Do not assert blind exception: `Exception`

This assertion message is a corollary of blind-except (BLE001).

Do not catch blind exception: {name}

Test Plan

cargo nextest run

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[MichaReiser]

Thanks