Function parse_github_folder_url 

pub fn parse_github_folder_url(url: &str) -> Option<ParsedGitUrl>

Parses a GitHub folder URL into its constituent parts. Handles the official format (.../tree/branch/path) as well as common “sloppy” formats like .../branch/path or just .../path (which assumes the default branch). Returns Some(ParsedGitUrl) if the URL is a parsable GitHub folder URL, otherwise None.