Run prettier command manually once and automatically on CI

[pdufour]

I noticed that there is a prettier config, but it doesn't look like the command has been ran in a while, so there are a lot of fixes applied when I run it. Therefore, I did the following:

1. manually ran it once
2. and also added a CI check step that will automatically check PR's with format:check

You may get some merge conflicts on PR's when / if this is merged, so for that I recommend the following steps:

Rebase steps

• On your branch
• git checkout main -- .prettierrc (I just made a minor change to max line length to align with existing code)
• npm run format
• Then merge in main, that way both files will be formatted and you shouldn't have issues

Test Plan

• I made a test commit that broke linting and see that the PR failed - https://github.com/pdufour/transformers.js/actions/runs/11924988068/job/33236295119

[xenova]

Hi there 👋 It was intentional to not yet run prettier until some open PRs had been merged (to keep the diffs small). So, while I won't merge this PR as is, I do think the .github/workflows/format-check.yml can be useful once we do. Is this something you can extract into a separate PR? Thanks!

[pdufour]

Hi, thanks for the quick response! Done - #1044.

[xenova]

Amazing! Thanks so much! 🤗