use cases

skipping out of active pairs
- this is easy, because we have the data about the pair from the overlay. Can work both inside and at the end
skipping out of inactive pairs
- when point is at the end and the closing delim is inserted
- when point is somewhere inside, the expression is properly balanced, and the closing delim is inserted

problems

string-like delims
- we need to be able to detect if we are skipping out or into such a structure
multi-char pairs. Is this worth it?