fixes serialization of regex pattern + description

[ProofOfKeags]

This fixes an issue introduced by #1498. We deflattened the structure due to issues with how the flattening algorithm caused the deserialization process to believe a pattern/description that was wrong to instead be missing. However, when we handrolled the Deserialize Implementation we also naively removed the flatten as well. This caused the Serialize implementation (which was still macro derived) to deflatten. This caused the front end to interpret what it expected (but did not check CC @elvece) to be a regex but instead was an object that had a regex and string row. Therefore U.test is not a function is a result of indexing into the object to find what it thought to be Regex.test but instead found nothing...because it was an object. Reintroducing the flatten directive will undo this process without altering how the Deserialize behaves.