Implement check_yaml as builtin hook

[lemorage]

Close #531

[j178]

Thanks! I’m a bit worried because we’re missing the --unsafe and --allow-multiple-documents features, and I know it’s pretty tough to implement these exactly in Rust.

I’m thinking we should only use our built-in implementation if the check-yaml hook doesn’t include --unsafe or --allow-multiple-documents arguments. Basically, we should improve our detection in the check_fast_path logic for better compatibility. What do you think?

[lemorage]

Fair considerations to me. But simply adding a special case to check_fast_path makes things bloated, also is not quite clean and extensible. If this is not a burden on your side, I can make this addition later.

[j178]

I added a basic check over at dc1ccf7, I think it's fine for now.

[lemorage]

Thx!