message: Use `core::convert::Infallible`
diff: @@ -98,9 +98,9 @@ enum PathOrStdin {
  }
  impl std::str::FromStr for PathOrStdin {
  - type Err = &'static str; // Unused, but satisfies `clap`. Could be `!` in the future.
  + type Err = std::convert::Infallible;
  - fn from_str(src: &str) -> Result<PathOrStdin, &'static str> {
  + fn from_str(src: &str) -> Result<PathOrStdin, std::convert::Infallible> {
  match src {
  "-" => Ok(PathOrStdin::StdIn),
  _ => Ok(PathOrStdin::Path(PathBuf::from(src))),
  