Improve finite functor error messages

[KevinDCarlson]

Fixes #598 by having @finfunctor tell the user which morphisms are mapped inconsistently with the object map. There is code ready to update @finfunctor to check preservation of equations between morphisms in the domain category, too, once we have some ability to check equality of homs.

[github-actions[bot]]

Review Checklist

Does this PR follow the development guidelines? Following is a partial checklist:

Tests

• [x] New features and bug fixes have unit tests
• [x] New modules have tests that are ultimately called by the test runner (test/runtests.jl)
• [x] Existing tests have not been deleted
• [x] Code coverage >= 90% or reduction justified in PR

Documentation

• [x] All exported functions, types, and constants have docstrings, written in complete sentences
• [x] Citations are given for any constructions, algorithms, or code drawn from external sources

Other

• [x] Style guidelines are followed, including indent width 2
• [x] Changes breaking backwards compatibility have been approved

[olynch]

@mehalter @KevinArlin, what's our feeling about the failing tests on nightly? Is this a bug in nightly? Should we disable nightly CI until it's fixed? I don't want to merge this with failing tests.

[epatters]

Oh, @KevinArlin, I see that in #765 you also add a get_unnaturalities function. I think I'd prefer a different naming convention but, more importantly, this does address my complaint about having inconsistent APIs for naturality and functorality testing.