Fix clippy::let_and_return

src/linalg/naive/dense_matrix.rs

@@ -29,8 +29,7 @@ impl<T: RealNumber> BaseVector<T> for Vec<T> {
     }
 
     fn to_vec(&self) -> Vec<T> {
-        let v = self.clone();
-        v
+        self.clone()
     }
 
     fn zeros(len: usize) -> Self {