If I see clippy/rust-analyzer lints while working should I fix them in the PR I'm working on or a separate one?
In this case the lint is
Shorthand struct initialization.
Depends. On code you've just modified or introduced? Or do the lints occur on the unmodified code?
If the former, fix them in the same commit so there's never a commit that produces the lints.
If the latter, separate PR.
While I personally prefer separate PR, I know that's not universally accepted. I'd put such fixes in a separate commit if nothing else.
Yes, definitely in a separate commit.