Keyset pagination doesn't work correctly for compound primary keys #190
Description
Consider https://datasette-issue-190-compound-pks.now.sh/compound-pks-9aafe8f/compound_primary_key
The next= link is to d,v:
But that page starts with:
The next key in the sequence should be d,w. Also we should return the full a-z of the ones that start with the letter e - in this example we only return e-w, e-x, e-y and e-z