## Summary Hi! This is my first PR to `ruff` and thanks for this amazing project. While I am working on my project, I need to set different rules for my `test/` folder and the main `src` package. It's not immediately obvious that the [`tool.ruff.per-file-ignores`](https://beta.ruff.rs/docs/settings/#per-file-ignores) support regular expression. It is useful to set rules on directory level. The PR add a simple example to make it clear this support regex.