Function ends_url_token 

fn ends_url_token(c: char) -> bool

Characters Url::as_str() percent-encodes in every component, so they cannot occur inside a rendered URL. Nothing may be added here without that guarantee: ), ,, | and ^ are legal in a path, and `, { and } are legal in a query or fragment; ending a URL on any of them would leave the tail after it in the output.