A non-empty comonadic list zipper
A Hoogle search reveals various implementations of zippers.
The two that have the most similar feature sets to nonempty-zipper are
list-zipper and non-empty-zipper.
list-zipper has a solid lens interface, and a ton of instances,
however it's lacking documentation and an NFData instance.
non-empty-zipper is most similar to this package but it
appears to be unmaintained (e.g. base has drifted).