Makes the UnknownCursor error more specific. There are several places with different logic where this error is returned (query not found, cursor mismatch, not enough items). Moves the error thrown on a query not being found in the store from UnknownCursor.
Context
UnknownCursorerror more specific. There are several places with different logic where this error is returned (query not found, cursor mismatch, not enough items). Moves the error thrown on a query not being found in the store fromUnknownCursor.Checklist
CONTRIBUTING.md.