Cleanup a dangling TODO after moving some syscall_types to from the
`main` crate to the `shadow_shim_helper_rs` crate to change all `use`
statements to use the new location directly instead of using a `pub use`
in the old location.

In previous discussion we agreed in theory on rustfmt's
`StdExternalCrate` grouping policy. Unfortunately we currently can't
use this in our default config, since it only works on nightly.

This is a one-time run of rustfmt using that policy with the nightly
compiler.

It cleans up the ordering both from the previous commit (which was
semi-automated using sed) and everywhere else.