Nightly clippy lints

[jjbayer]

This PR fixes warnings raised by

cargo +nightly clippy -p argmin --all-targets --features "_full_dev" -- -D warnings

around stricter unused_imports checks.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.42%. Comparing base (35e00e2) to head (bfdd49d).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #488      +/-   ##
==========================================
- Coverage   92.42%   92.42%   -0.01%     
==========================================
  Files         178      178              
  Lines       24314    24314              
==========================================
- Hits        22472    22471       -1     
- Misses       1842     1843       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[stefan-k]

Thanks a lot! :)