Remove unnecessary `any(target_os = "redox", unix)`, change to just `unix`. [This](https://github.com/BurntSushi/same-file/blob/master/src/lib.rs#L85) used to be necessary, but in 2019 [Redox became unix-family](https://github.com/rust-lang/rust/pull/60547).
Remove unnecessary
any(target_os = "redox", unix), change to justunix.This used to be necessary, but in 2019 Redox became unix-family.