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_dynamic_programming/climbing_stairs_dfs.rs

@@ -1,27 +1,29 @@
-/*
- * File: climbing_stairs_dfs.rs
- * Created Time: 2023-07-09
- * Author: codingonion (coderonion@gmail.com)
- */
-
-/* 搜索 */
-fn dfs(i: usize) -> i32 {
-    // 已知 dp[1] 和 dp[2] ，返回之
-    if i == 1 || i == 2 { return i as i32; }
-    // dp[i] = dp[i-1] + dp[i-2]
-    let count = dfs(i - 1) + dfs(i - 2);
-    count
-}
-
-/* 爬楼梯：搜索 */
-fn climbing_stairs_dfs(n: usize) -> i32 {
-    dfs(n) 
-}
-
-/* Driver Code */
-pub fn main() {
-    let n: usize = 9;
-
-    let res = climbing_stairs_dfs(n);
-    println!("爬 {n} 阶楼梯共有 {res} 种方案");
-}
+/*
+ * File: climbing_stairs_dfs.rs
+ * Created Time: 2023-07-09
+ * Author: codingonion (coderonion@gmail.com)
+ */
+
+/* 搜索 */
+fn dfs(i: usize) -> i32 {
+    // 已知 dp[1] 和 dp[2] ，返回之
+    if i == 1 || i == 2 {
+        return i as i32;
+    }
+    // dp[i] = dp[i-1] + dp[i-2]
+    let count = dfs(i - 1) + dfs(i - 2);
+    count
+}
+
+/* 爬楼梯：搜索 */
+fn climbing_stairs_dfs(n: usize) -> i32 {
+    dfs(n)
+}
+
+/* Driver Code */
+pub fn main() {
+    let n: usize = 9;
+
+    let res = climbing_stairs_dfs(n);
+    println!("爬 {n} 阶楼梯共有 {res} 种方案");
+}