Does not re-stage changes to partial files

[motiz88]

Originally reported by @Stupidism in #5 (comment):

When I want to commit partial files, it can't add fixed part.

[motiz88]

This is the intended behaviour. I don't foresee it changing unless someone makes a very compelling case for a specific thing we can always safely do with partially staged files, which will never trash anyone's commits.

[Stupidism]

If you are OK with git stash

I did figure sth out with git stash
https://github.com/Stupidism/react-starter-kit/blob/feature/perfect-lint-staged/package.json#L209-L216

[motiz88]

@Stupidism I'm afraid I can't look into that right now but I'm all for further discussion here.