message: Extract `two_kinds_of_msg_format_err` message to de-duplicate it
diff: @@ -469,25 +469,26 @@ pub trait ArgMatchesExt {
  ansi: false,
  render_diagnostics: false,
  };
  + let two_kinds_of_msg_format_err = "cannot specify two kinds of `message-format` arguments";
  for fmt in self._values_of("message-format") {
  for fmt in fmt.split(',') {
  let fmt = fmt.to_ascii_lowercase();
  match fmt.as_str() {
  "json" => {
  if message_format.is_some() {
  - bail!("cannot specify two kinds of `message-format` arguments");
  + bail!(two_kinds_of_msg_format_err);
  }
  message_format = Some(default_json);
  }
  "human" => {
  if message_format.is_some() {
  - bail!("cannot specify two kinds of `message-format` arguments");
  + bail!(two_kinds_of_msg_format_err);
  }
  message_format = Some(MessageFormat::Human);
  }
  "short" => {
  if message_format.is_some() {
  - bail!("cannot specify two kinds of `message-format` arguments");
  + bail!(two_kinds_of_msg_format_err);
  }
  message_format = Some(MessageFormat::Short);
  }
  @@ -499,7 +500,7 @@ pub trait ArgMatchesExt {
  Some(MessageFormat::Json {
  render_diagnostics, ..
  }) => *render_diagnostics = true,
  - _ => bail!("cannot specify two kinds of `message-format` arguments"),
  + _ => bail!(two_kinds_of_msg_format_err),
  }
  }
  "json-diagnostic-short" => {
  @@ -508,7 +509,7 @@ pub trait ArgMatchesExt {
  }
  match &mut message_format {
  Some(MessageFormat::Json { short, .. }) => *short = true,
  - _ => bail!("cannot specify two kinds of `message-format` arguments"),
  + _ => bail!(two_kinds_of_msg_format_err),
  }
  }
  "json-diagnostic-rendered-ansi" => {
  @@ -517,7 +518,7 @@ pub trait ArgMatchesExt {
  }
  match &mut message_format {
  Some(MessageFormat::Json { ansi, .. }) => *ansi = true,
  - _ => bail!("cannot specify two kinds of `message-format` arguments"),
  + _ => bail!(two_kinds_of_msg_format_err),
  }
  }
  s => bail!("invalid message format specifier: `{}`", s),
  