SYSML2 — RequirementConstraintUsage should not have a RequirementBody

In the textual notation grammar, RequirementConstraintUsage produces a ConstraintUsage, but the first alternative in the production allows the ConstraintUsage to have a RequirementBody. The RequirementBody production allows kinds of declarations (such as subjects and actors) that are not valid in the body of a ConstraintUsage (because of validation constraints such as validateSubjectMembershipOwningType, validateActorMembershipOwningType, etc.). There is no point in syntactically allowing owned members that are then invalid, so the first alternative in RequirementConstraintUsage should have a CalculationBody (like the second alternative) rather than a RequirementBody.