Should John Smith VI MD read like John Smith III MD? #784

Today a roman numeral before a credential reads two ways depending on its spelling:

The difference is that numerals are recognized two ways. ii, iii and iv (and i, v) are suffix vocabulary; vi through x are read by shape alone, by S10's trailing-numeral fork (_vocab._ROMAN, I–X). S8's credential run asks the vocabulary whether a word starts the run, so a listed numeral starts it and a shape-only one does not; S10 then reads a numeral with a credential behind it as an ordinary name word (its Accepted clause).

Questions:

1. Should a numeral read as a generation before a credential, whatever its spelling?
2. Do we still want two recognizers, vocabulary for some numerals and shape for others, or one predicate that every rule asks (mechanisms.md#ONE-PREDICATE-PER-QUESTION)? AGENTS.md's spelling sweep records this split as a recurring source of bugs (Two stages hand-copy each other's trailing-word logic after #601/#602; share one predicate each #610, Should a known suffix right before a comma make it a suffix comma? Fabio Martini II, AD reads given AD, family Fabio Martini #656).

Found by the S-section skeleton migration (#761, PR #783).