Respect `linguist-generated` git attribute

[drivasperez]

I'm already finding this useful, so thanks! The monorepo at my work has a lot of autogenerated files, and most substantial changes end up regenerating them, which can lead to quite noisy diffs. Github's code review view will auto-hide files marked as linguist-generated or binary in the repo .gitattributes file, and I think it'd be useful to replicate that here?

Happy to put up a PR, but thought I'd open an issue first to see if you agree. I think the best approach is probably to shell out to git if in a git repo (or git-colocated jj repo) and run git attr, rather than parse the .gitattributes file in node, as I think the logic for git attributes can get pretty gnarly.

[david-crespo]

What you describe above sounds more like what I had in mind. Is your PR complete different or am I misunderstanding?

#19 (comment)

[drivasperez]

The PR does both:

• Reads git attributes for the linguist-generated attribute: these are the user-specified patterns which you can set as globs in a .gitattributes file. E.g. we have **/generated/**/* as a pattern in ours.

• Implements a lot of default rules to match as many common patterns as possible, which I think is how most people interact with the "autogenerated file" feature in GitHub.

I should probably have split these into separate PRs, apologies!