Next item/s in a list
next x next[x]
Where x is a list, for each item in x, returns the next item.
For the last item, it returns a null if the list is a vector, otherwise an empty list ().
q)next 2 3 5 7 11
3 5 7 11 0N
q)next (1 2;"abc";`ibm)
"abc"
`ibm
`int$()
Duration of a quote:
q)update (next time)-time by sym from quote
next is a uniform function.