Fix clippy warnings

[Luni-4]

This PR fixes clippy warnings introduced by Rust 1.59

[codecov-commenter]

Codecov Report

Merging #794 (f035f19) into master (d488b6e) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #794      +/-   ##
==========================================
- Coverage   39.94%   39.91%   -0.03%     
==========================================
  Files          51       51              
  Lines        6827     6827              
  Branches      975      975              
==========================================
- Hits         2727     2725       -2     
  Misses       3439     3439              
- Partials      661      663       +2     

Impacted Files	Coverage Δ
src/langs.rs	90.00% <0.00%> (-10.00%)	⬇️
src/metrics/loc.rs	80.28% <0.00%> (-0.25%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d488b6e...f035f19. Read the comment docs.