KERML — The checkFeatureEndSpecialization constraint should apply to Connectors as well as Associations

The checkFeatureEndSpecialization semantic constraint requires that

If a Feature has isEnd = true and an owningType that is an Association, then it must directly or indirectly specialize Links::Link::participants from the Kernel Semantic Library.

If a Connector is explicitly typed by one or more Associations, then it’s ends will redefine the corresponding Association ends and will thus also indirectly specialize Link::participants. However, if the Connector adds additional ends, then these will not redefine any Association ends and there is currently no requirement that these ends specialize Link::participants. In particular, the base Association Link has no ends, so when an n-ary Connector is implicitly typed by it, none of its ends will redefine Association ends, and so none of them will subset participants, which is semantically incorrect.

The checkFeatureEndSpecialization constraint needs to be updated to also cover such cases.