ruff

62f1ee08 - [`refurb`] Implement `single-item-membership-test` (`FURB171`) (#7815)

[`refurb`] Implement `single-item-membership-test` (`FURB171`) (#7815) ## Summary Implement [`no-single-item-in`](https://github.com/dosisod/refurb/blob/master/refurb/checks/iterable/no_single_item_in.py) as `single-item-membership-test` (`FURB171`). Uses the helper function `generate_comparison` from the `pycodestyle` implementations; this function should probably be moved, but I am not sure where at the moment. Update: moved it to `ruff_python_ast::helpers`. Related to #1348. ## Test Plan `cargo test`