KERML_ — Semantic constraint needed for result type of a "constructor" expression

In the KerML semantics, 8.4.4.9.4 Invocation Expressions, the semantic equivalent model for an InvocationExpression used as a "constructor" for a type T (i.e., T(...)) is shown as having its result parameter redefined with a FeatureTyping relationship to T. However, there is no semantic constraint in the abstract syntax to enforce this. Note that this typing is important, because it is to be expected that the result of a constructor is of the type being constructed.

Add semantic constraint

It is agreed that there should be a semantic constraint as indicated in the issue. This should be a constraint on Feature, similar to the current checkFeatureResultSpecialization, which covers specifically the results of FeatureReferenceExpressions. (Note that this proposal is consistent with the proposed resolution KERML_-78 to KERML_-67.)