satisfy clippy

src/ica.rs

@@ -204,7 +204,7 @@ where
         let k = unsafe { k.assume_init() };
         let mut x1 = k.dot(&x);
         let n_features_sqrt = A::from_usize(n_features).expect("approximation").sqrt();
-        for x_elem in x1.iter_mut() {
+        for x_elem in &mut x1 {
             *x_elem *= n_features_sqrt;
         }
 
@@ -386,7 +386,7 @@ where
     A: Scalar,
     S: DataMut<Elem = A>,
 {
-    for elem in input.iter_mut() {
+    for elem in &mut input {
         *elem = elem.tanh();
     }
     let ncols = A::from_usize(input.ncols()).expect("approximation");