CTS213 — CTS2: Children/Descendants use inconsistent with Value Set

The EntityDescription model provides hooks for children and descendants, the interpretation of which is left to the service. Value Set Definition, however, provides no equivalent ability where, instead, the associatedEntities have to provide the specific predicate.

Would recommend making the predicate optional and, if present, describing the exact behavior that the service needs to exhibit.

Logged: https://github.com/cts2/cts2-specification/issues/165