unit test - no such thing as a reference datum

[JaredCorduan]

Description

I have added a unit test to demonstrate that "there is no such thing as a reference datum". In other words, you cannot include a reference input that contains an inline datum and have it count for the datum witness where ever it is needed.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated (See RELEASING.md)
• Any changes are noted in the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[lehins]

👍

[teodanciu]

Looks good to me