fix: Fix new clippy warnings

[morenol]

This fixes the clippy warnings added in the new version of clippy

[morenol]

There is still an error with this clippy::suspicious-operation-groupings. Could you check that @VolodymyrOrlov? It looks to me that we can ignore that warning

[VolodymyrOrlov]

lgtm

[VolodymyrOrlov]

I am wondering what is faster in Rust, mu * mu or mu.powi(2)? I always thought that multiplication is faster but that might not be true in Rust. This might be a small thing, but if repeated many times the difference will accumulate to a significant value.

[VolodymyrOrlov]

nm, I found my answer here: https://stackoverflow.com/questions/38799724/is-there-a-performance-difference-between-a-squared-function-and-directly-callin

[VolodymyrOrlov]

There is still an error with this clippy::suspicious-operation-groupings. Could you check that @VolodymyrOrlov? It looks to me that we can ignore that warning

Agree, the warnings I see do not make any sense. The logic that is highlighted by the lint is correct

[codecov-io]

Codecov Report

Merging #79 (4f1c7ff) into development (745d0b5) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

@@               Coverage Diff               @@
##           development      #79      +/-   ##
===============================================
- Coverage        84.17%   84.09%   -0.08%     
===============================================
  Files               78       78              
  Lines             8081     8080       -1     
===============================================
- Hits              6802     6795       -7     
- Misses            1279     1285       +6     

Impacted Files	Coverage Δ
src/optimization/first_order/lbfgs.rs	92.85% <ø> (ø)
src/linalg/mod.rs	53.98% <100.00%> (ø)
src/linalg/stats.rs	95.65% <100.00%> (ø)
src/linear/lasso_optimizer.rs	94.11% <100.00%> (ø)
src/algorithm/sort/quick_sort.rs	91.35% <0.00%> (-1.24%)	⬇️
src/naive_bayes/gaussian.rs	83.15% <0.00%> (-1.06%)	⬇️
src/ensemble/random_forest_classifier.rs	71.15% <0.00%> (-0.97%)	⬇️
src/model_selection/kfold.rs	86.48% <0.00%> (-0.91%)	⬇️
src/linalg/naive/dense_matrix.rs	79.55% <0.00%> (-0.30%)	⬇️
src/svm/svc.rs	89.62% <0.00%> (ø)
... and 1 more

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[morenol]

Merging because it already was approved