Function conforms 

pub fn conforms(branch: &str) -> bool

Both the rule and the message now come from vocabulary, so what a user is told and what is enforced cannot drift — and neither can the branch prefixes and the commit types, which had diverged to the point that docs/… was unpushable while docs: was a valid commit type.

[[:alnum:]] is ASCII in both rg and grep -E under the C locale, which is what the shell version enforced; is_ascii_alphanumeric keeps that. A Unicode-aware check would silently LOOSEN the rule.