Fix wrong typo

README.md

@@ -830,7 +830,7 @@ Write code on a whiteboard or paper, not a computer. Test with some sample input
         - [ ] is_empty() - returns true if heap contains no elements
         - [ ] extract_max - returns the max item, removing it
         - [ ] sift_down - needed for extract_max
-        - [ ] remove(i) - removes item at index x
+        - [ ] remove(x) - removes item at index x
         - [ ] heapify - create a heap from an array of elements, needed for heap_sort
         - [ ] heap_sort() - take an unsorted array and turn it into a sorted array in-place using a max heap
             - note: using a min heap instead would save operations, but double the space needed (cannot do in-place).