Run cargo clippy --fix (#250)

* Run `cargo clippy --fix`
* Run `cargo clippy --all-features --fix`
* Fix other clippy warnings
* cargo fmt

Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>

src/svm/svr.rs

@@ -662,7 +662,7 @@ mod tests {
         .unwrap();
 
         let t = mean_squared_error(&y_hat, &y);
-        println!("{:?}", t);
+        println!("{t:?}");
         assert!(t < 2.5);
     }