The sub-title "Recursion in C" was missing (#18996)

In line 96, the subtitle was not appropriately mentioned.

client/src/pages/guide/english/c/functions/index.md

@@ -93,7 +93,7 @@ You may have observed a similar issue with things like if statements and any of
 
 Ideally, you'll always pass into your functions as parameters, but you may not always be able to. Picking the best solution is your job as a programmer.
 
-Recursion in C
+## Recursion in C
 When function is called within the same function, it is known as recursion in C. The function which calls the same function, is known as recursive function.
 ```
 int factorial (int n)