fix needless-range and clippy::ptr_arg warnings. (#36)

* Fix needless for loop range

* Do not ignore clippy::ptr_arg

src/metrics/auc.rs

@@ -68,8 +68,8 @@ impl AUC {
                     j += 1;
                 }
                 let r = T::from_usize(i + 1 + j).unwrap() / T::two();
-                for k in i..j {
-                    rank[k] = r;
+                for rank_k in rank.iter_mut().take(j).skip(i) {
+                    *rank_k = r;
                 }
                 i = j - 1;
             }