ListSort provides a stable implementation of merge sort through its sort
method. It has a O(N.log(N)) complexity and does not require additional memory allocation.
Static methods
staticinlinesort<T>(list:T, cmp:(T, T) ‑> Int):T
Sorts List lst according to the comparison function cmp, where
cmp(x,y) returns 0 if x == y, a positive Int if x > y and a
negative Int if x < y.
This operation modifies List a in place and returns its head once modified.
The prev of the head is set to the tail of the sorted list.
If list or cmp are null, the result is unspecified.