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

* Fix needless for loop range

* Do not ignore clippy::ptr_arg

src/optimization/line_search.rs

@@ -41,7 +41,7 @@ impl<T: Float> Default for Backtracking<T> {
 }
 
 impl<T: Float> LineSearchMethod<T> for Backtracking<T> {
-    fn search<'a>(
+    fn search(
         &self,
         f: &(dyn Fn(T) -> T),
         _: &(dyn Fn(T) -> T),