SYSML2_ — TransitionUsage source and target properties do not support feature chains

According to the SysML abstract syntax (8.3.17.9 TransitionUsage), the source and target of a TransitionUsage must be ActionUsages. However, the textual notation (8.2.2.17.3 Transition Usages) allows sources and targets to be feature chains, which are parsed as a KerML Feature with FeatureChaining relationships to the chained Features, which are not ActionUsages.

Update derivation constraints

The identified problem can be resolved by revising derivation constraints deriveTransitionUsageSource and deriveTransitionUsageTarget to use the Feature::featureTarget property added by the resolution to KERML_-37.