[feature] stylish-haskell as a pre-commit hook

[LucBro]

Hello, i've tried to add pre-commit support for users of stylish-haskell.

You can test it, by

• cloning my fork locally
• create a a new folder e.g. Example outside the stylish-haskell repo
  • cd Example
  • git init
  • add mail and name to git
  • copy example/Bad.hs from the stylish-haskell repo to your folder Example
  • git add Bad.hs
  • git commit -m "initial commit"
  • pre-commit try-repo your/local/path/to/repo/stylish-haskell/ --all-files
    • execute it twice, as it will fail the first time
• Bad.hs should be formatted now

EDIT: additional:

• create a .pre-commit-config.yaml in the repo Example with:

repos:
-   repo: https://github.com/LucBro/stylish-haskell.git
    rev: feature/pre-commit
    hooks:
    -   id: stylish-haskell

• change Bad.hs
• commit your changes

/EDIT

Be aware that the try-repo command of pre-commit works with HEAD of the local stylish-haskell repo, so commit your changes of .pre-commit-hooks.yaml. The --all-files argument ensures that your Bad.hs is not skipped (and that's the reason why I don't use the command in stylish-haskell/examples, as it would change every .hs file in the repo).

Pre-commit uses cabal to install stylish-haskell. I've tested this with ghc 9.8.2 and cabal 3.10.3.0.

---

People should be able to use now stylish-haskell in pre-commit by adding this to their .pre-commit-config.yaml and running pre-commit run --all-files or committing in their haskell project repo.

repos:
-   repo: https://github.com/haskell/stylish-haskell.git
# main for the rev:  section is possible, but `pre-commit` will complain
    rev: release/X.Y.Z
    hooks:
    -   id: stylish-haskell

Thank you Greetings LucBro