add precision about the nature of the comparator function
add precision about the nature of the comparator function

aureooms/js-merging,aureooms/js-heapsort,aureooms/js-in-situ-sort-spec,aureooms/js-selection,aureooms/js-mergesort,aureooms/js-quicksort,aureooms/js-sort,aureooms/js-partition