fix: replace c++ with cpp for language postfix

guide/english/algorithms/sorting-algorithms/bubble-sort/index.md

@@ -108,7 +108,7 @@ public class BubbleSort {
 }
 ```
 ### Example in C++
-```c++
+```cpp
 // Recursive Implementation
 void bubblesort(int arr[], int n)
 {

guide/english/algorithms/sorting-algorithms/heap-sort/index.md

@@ -64,7 +64,7 @@ public class Heapsort {
 }
 ```
 Implementation in C++
-```C++
+```cpp
 #include <iostream>
 using namespace std;
 void heapify(int arr[], int n, int i)