Submit Subscriber's Name in Reference.display

Will update the description for Coverage.subscriber to add ‘Provide the name of the subscriber in Coverage.subscriber.display concatenating the subscriber’s prefix, given name, family name and suffix (in this order), each separated by a single space. If discrete name parts are required, a Patient resource SHALL be pointed to in Coverage.subscriber.reference."  Will leave Coverage.subscriber as 0..1, but will change the cardinality of Coverage.subscriber.display to 1..1 to ensure a display name is always present.