Function is_prerelease 

pub fn is_prerelease(version: &str) -> bool

Detects if a Maven version string is a pre-release.

A version is a pre-release when any of its segments is a qualifier that ranks below the release qualifier in qualifier_rank (alpha, beta, milestone/M, rc/cr, snapshot, …) — the same table compare_versions uses for ordering, so this can never disagree with the comparator about whether a version is a base release or a pre-release.