message: Rewrite an example of `option.map()`
  Closes:
  Approved by: metajack
diff: @@ -310,11 +310,7 @@ impl AwsLogThread {
  fn log_stream_to_validator_short_str(&self, s: &str) -> Option<String> {
  let cap = self.re_validator.captures(s);
  - if let Some(cap) = cap {
  - Some(cap[1].into())
  - } else {
  - None
  - }
  + cap.map(|cap| cap[1].into())
  }
  fn parse_commit_log_entry(&self, e: &LogEntry) -> Option<Commit> {
  