pub fn verb_stem(token: &str) -> Option<String>Expand description
Extract the verb stem from a first-word token by stripping any trailing non-alphabetic suffix (dash, slash, number, etc.).
Returns the lowercase stem, or None if the leading run is all uppercase
(acronym like API/NFC) or there are no leading ASCII letters \u{2014}
those are skipped for conversion since they aren’t verbs.