**tails** +containers

*O(n)*. Returns a sequence of all suffixes of this sequence, longest first. For example,
> tails (fromList "abc") = fromList [fromList "abc", fromList "bc", fromList "c", fromList ""]
Evaluating the *i*th suffix takes *O(log(min(i, n-i)))*, but evaluating every suffix in the sequence takes *O(n)* due to sharing.