Support `cfi:{start}-{end}` queries which filter annotations based on whether
they have an associated EPUB CFI which lies in `[start, end)`.

This query can be entered manually by the user in the search box, which is
useful for testing, but the intent is that this filter would be used in contexts
where the query is generated automatically (eg. as a result of a user making a
selection from the book's table of contents).