Function heap_sort

src/fl/stl/algorithm.h:398–407

template <typename Iterator, typename Compare>
void heap_sort(Iterator first, Iterator last, Compare comp) FL_NOEXCEPT {
    heapify(first, last, comp);
    
    Iterator end = last - 1;
    while (end > first) {
        swap(*end, *first);
        sift_down(first, first, end - 1, comp);
        --end;
    }
}

// Quicksort implementation
template <typename Iterator, typename Compare>