Update binary_search_exercise.md

##

Author: geeky-me

algorithms/1_BinarySearch/binary_search_exercise.md

@@ -1,4 +1,4 @@
-### Binary Search Exercise
+##### Binary Search Exercise
 1. When I try to find number 5 in below list using binary search, it doesn't work and returns me -1 index. Why is that?
 
     ```numbers = [1,4,6,9,10,5,7]```
@@ -11,4 +11,4 @@
     ```
    This should return 5,6,7 as indices containing number 15 in the array
     
-[Solution](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/1_BinarySearch/binary_search_exercise_solution.py)    
+[Solution](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/1_BinarySearch/binary_search_exercise_solution.py)