clarify the two directions of ONE OF

[mengwong]

if there are sameDepth values going vertically, then each row is an enum constructor made of multiterms

if there is only one row going horizontally, then each column is an enum constructor, and we fmap pure over each MTExpr to upgrade each MTExpr to a MultiTerm

HAS  color  IS  ONE OF  Red
                        Green
                        Blue

vs

HAS  color  IS  ONE OF  Red  Green  Blue

allegedly a vertical could be a paramtext with nested values but we need to investigate that a bit.