- less stricter BnfiTermCopy + typesafe changes
- Decoration.None is not null anymore
- fix for UnparseHint handling in GetChildrenPriority
- normal keyterms are also allowed in a choice expression, not just punctuation keyterms
- typesafety tests updated
- BnfiTermCopy.Rule has BnfiExpressionChoice as type again
better BnfiTermNoAst