Function non_uri_join 

pub fn non_uri_join(left: &str, right: &str, fmt: PathFormat) -> String

Join two path strings without recognizing URIs as absolute.

Like join, but does not check is_absolute(right). Use when right has already been determined to be non-absolute via a URI-unaware check (e.g., is_absolute without URI recognition). This prevents scheme://... strings from being treated as absolute when URI support is disabled.