Realign indentation and checkstyle of bracket (#29205)

* Realign indentation and checkstyle of bracket

* Update index.md

guide/english/cplusplus/vector/index.md

@@ -196,12 +196,11 @@ int main(){
 }
 ```
 In C++11, you can also sort with lambda function, which can be useful.
-```cpp11
+```cpp
-#include<bits/stdc++.h>
+#include <bits/stdc++.h>
 using namespace std;
 
-int main()
+int main(){
-{
     vector<int > v {3, 1, 2};
     sort(v.begin(), v.end(), [] (int i, int j) -> bool {
         return i < j;