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_divide_and_conquer/binary_search_recur.rs

@@ -7,7 +7,9 @@
 /* 二分查找：问题 f(i, j) */
 fn dfs(nums: &[i32], target: i32, i: i32, j: i32) -> i32 {
     // 若区间为空，代表无目标元素，则返回 -1
-    if i > j { return -1; }
+    if i > j {
+        return -1;
+    }
     let m: i32 = (i + j) / 2;
     if nums[m as usize] < target {
         // 递归子问题 f(m+1, j)
@@ -31,7 +33,7 @@ fn binary_search(nums: &[i32], target: i32) -> i32 {
 /* Driver Code */
 pub fn main() {
     let target = 6;
-    let nums = [ 1, 3, 6, 8, 12, 15, 23, 26, 31, 35 ];
+    let nums = [1, 3, 6, 8, 12, 15, 23, 26, 31, 35];
 
     // 二分查找（双闭区间）
     let index = binary_search(&nums, target);