[mbrunnen]

Fixes #21.

validateFunctionResultParameterMembership and
validateExpressionResultParameterMembership now count the return
parameters of the most specific owners in the closure of the type, not only
the owned ones. An owned return parameter redefines those of the general
types, so function K :> F, H { return t; } stays valid.

How to test

$ cargo test -p sysmlv2-model --lib inherited_return_parameters_count
$ cargo test -p sysmlv2-parser --test integration opensysml::

Look closely at

• Owners in the library are left out. The check facts hold no implied
  specializations, so two library bases look unrelated: checked as user
  files, the Systems Library gives 13 false findings in Requirements.sysml,
  VerificationCases.sysml and Views.sysml. As a result,
  function G :> LibF, H, with a return in a library function and in a user
  function, is still missed. A full fix needs the implied supertypes in the
  facts.
• The opensysml baselines gain one finding on
  probes/validateCalculationUsageType.sysml: calc c : C1, C2; inherits a
  return parameter from each type. The corpus findings
  (spec-refs/SysML-v2-Release, apollo-11-sysml-v2) do not change.
• The CHANGELOG.md entry is under a new Unreleased heading. Move or drop
  it as you prefer.