contents: khan academy link for binary search fixed (#604)

Co-authored-by: Tamás Bürger <tamasburger@Tamass-MBP.box>

apps/website/contents/algorithms/sorting-searching.md

@@ -33,7 +33,7 @@ While you're unlikely to be asked to implement a sorting algorithm from scratch
 
 - Readings
   - [Sorting Out The Basics Behind Sorting Algorithms](https://medium.com/basecs/sorting-out-the-basics-behind-sorting-algorithms-b0a032873add), basecs
-  - [Binary Search](https://www.khanacademy.org/computing/computer-science/algorithms/binary-search/), Khan Academy
+  - [Binary Search](https://www.khanacademy.org/computing/computer-science/algorithms/binary-search/a/binary-search), Khan Academy
 - Additional (only if you have time)
   - [Exponentially Easy Selection Sort](https://medium.com/basecs/exponentially-easy-selection-sort-d7a34292b049), basecs
   - [Bubbling Up With Bubble Sorts](https://medium.com/basecs/bubbling-up-with-bubble-sorts-3df5ac88e592), basecs