UML23 — Remove InputPint from StructuredActivities

My inclination would be to remove StructuredActivities::InputPin, and have it only in CompleteStructuredActivities, with OutputPin in both StructuredActivities and CompleteStructuredActivities. The constraints, if they are in the model at all in their unformalized form, should only be on the InputPin and OutputPin classes in CompleteStructuredActivities. Then we can deal as a separate issue with the proper constraints for flows into and out of OutputPins and InputPins at L1 and L2."

Make InputPin only coming from CompleteStructuredActivities (and remove it from StructuredActivities in the metamodel).
Then, for OutputPin sections add "Package CompleteStructuredActivities" as a subheading for the constraint (and move it in the metamodel to the counterparts in that package).