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_stack_and_queue/deque.rs

@@ -12,16 +12,16 @@ use std::collections::VecDeque;
 pub fn main() {
     // 初始化双向队列
     let mut deque: VecDeque<i32> = VecDeque::new();
-    deque.push_back(3);     
+    deque.push_back(3);
     deque.push_back(2);
     deque.push_back(5);
     print!("双向队列 deque = ");
     print_util::print_queue(&deque);
 
     // 访问元素
-    let peek_first = deque.front().unwrap();   
+    let peek_first = deque.front().unwrap();
     print!("\n队首元素 peekFirst = {peek_first}");
-    let peek_last = deque.back().unwrap();     
+    let peek_last = deque.back().unwrap();
     print!("\n队尾元素 peekLast = {peek_last}");
 
     /* 元素入队 */
@@ -47,4 +47,4 @@ pub fn main() {
     // 判断双向队列是否为空
     let is_empty = deque.is_empty();
     print!("\n双向队列是否为空 = {is_empty}");
-}
+}