chore(docs): update ruff_linter crate name in CONTRIBUTING.md (#10745)
Reading through `CONTRIBUTING.md`, I happened to notice that it still
referred to the `ruff_linter` crate as the `ruff` crate. `ruff` is a
different crate, located in `crates/ruff`, which doesn't contain "the
vast majority of the code and all the lint rules."