message: Check every input line for key material in SecretKey::from_data
  This fixes a regression added while implementing SSH support, where only
  the first line of an age keyfile (a comment) would be parsed, returning
  no keys.
diff: @@ -56,7 +56,12 @@ impl SecretKey {
  let mut buf = String::new();
  loop {
  match read::secret_keys(&buf) {
  - Ok((_, keys)) => break Ok(keys),
  + Ok((_, keys)) => {
  + // Ensure we've found all keys in the file
  + if data.read_line(&mut buf)? == 0 {
  + break Ok(keys);
  + }
  + }
  Err(nom::Err::Incomplete(nom::Needed::Size(_))) => {
  data.read_line(&mut buf)?;
  }
  