Cargo fmt

[seddonym]

I just realised cargo fmt wasn't running in CI, this fixes formatting errors and adds it to CI.

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #248 will not alter performance

_{Comparing cargo-fmt (167e6e9) with main (e7e1d8d)¹}

Summary

✅ 23 untouched benchmarks

Footnotes

1. No successful run was found on main (167e6e9) during the generation of this report, so e7e1d8d was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩