## 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`