FHIR's modeling style gives singular names to fields with multiple cardinality (e.g. "Obseravtion.related", or "Bundle.entry"). But the documentation of these fields is inconsistent: some are documented in the pluraal ("Observations related to this observation") while others are documented in the singular ("Entry in the bundle"). We should document these fields in a consistent way. (I'd pick singular to match the field names, but consistency is all I seek.)