Add autofix for `PYI030` (#7934)
## Summary
Part 2 of implementing the reverted autofix for `PYI030`
Also handles `typing.Union` and `typing_extensions.Literal` etc, uses
the first subscript name it finds for each offensive line.
## Test Plan
<!-- How was it tested? -->
`cargo test` and manually
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Co-authored-by: Zanie Blue <contact@zanie.dev>
