cargo fmt rust code (#1131)

* cargo fmt code

* Add empty line to seperate unrelated comments

* Fix review

* Update bubble_sort.rs

* Update merge_sort.rs

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/rust/chapter_tree/binary_tree.rs

@@ -3,7 +3,6 @@
  * Created Time: 2023-02-27
  * Author: xBLACKICEx (xBLACKICE@outlook.com)
  */
-
 use std::rc::Rc;
 include!("../include/include.rs");
 use tree_node::TreeNode;
@@ -37,4 +36,4 @@ fn main() {
     n1.borrow_mut().left = Some(Rc::clone(&n2));
     println!("\n删除节点 P 后\n");
     print_util::print_tree(&n1);
-}
+}