Update README.md

Author: bassantgz30

README.md

@@ -108,8 +108,8 @@ Big-Theta refers to the tight bound of time or space complexity of an algorithm.
 - Indexing:         Linked Lists: `O(n)`
 - Search:           Linked Lists: `O(n)`
 - Optimized Search: Linked Lists: `O(n)`
-- Append:			Linked Lists: `O(1)`
-- Prepend:			Linked Lists: `O(1)`
+- Append:           Linked Lists: `O(1)`
+- Prepend:			    Linked Lists: `O(1)`
 - Insertion:        Linked Lists: `O(n)`