Properly handle positional recipe arguments#68

From the just [readme](https://github.com/casey/just?tab=readme-ov-file#positional-arguments-1): > The positional-arguments setting causes all arguments to be passed as positional arguments, allowing them to be accessed with $1, $2, …, and $@, which can be then double-quoted to avoid further splitting by the shell: ```make set positional-arguments foo argument: touch "$1" ``` We shouldn't warn for unused parameters here. This is a bit tricky since we'd have to detect for proper usages of `$1`, `$2`, etc. for each arguments.