Reduce relationship error verbosity

[dcousens]

The scenario where an invalid 3-way relationship is defined, the error presented is quite verbose:

Foo.bar points to Abc.def, Abc.def points to Foo, expected Abc.def to point to Foo.bar

This pull request changes that error to be equivalent to the following, which is aligned with each of the other relationship errors in structure of {context}, but {problem}.

Foo.bar expects Abc.def to be a two way relationship, but Abc.def points to Foo.bazzz

[codesandbox-ci]

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