message: Use splitn to resolve mapdir bug on Windows
diff: @@ -30,7 +30,7 @@ pub fn parse_mapdir(entry: &str) -> Result<(String, PathBuf)> {
  retrieve_alias_pathbuf(alias, real_dir)
  }
  // And then we try splitting by `:` (for compatibility with previous API)
  - else if let [alias, real_dir] = entry.split(':').collect::<Vec<&str>>()[..] {
  + else if let [alias, real_dir] = entry.splitn(2, ':').collect::<Vec<&str>>()[..] {
  retrieve_alias_pathbuf(alias, real_dir)
  } else {
  bail!(
  