Unicode 11 comes out in June, and we should update to it.

There are a bunch of changes to the grapheme and word stuff involved here. Most of the complex emoji rules have been replaced with things using\p{Extended_Pictographic}, which is not a disjoint grapheme category, rather it is an additional property. This crate may require some refactoring.

We may want to update to Unicode 10 before that; that should be a straightforward regen of the tables IIRC.