message: Switch to split_once
  Summary: Better to use the standard function that the one in Gazebo, now it's been out a while. Will deprecate the Gazebo one in a future diff.
diff: @@ -429,7 +429,7 @@ fn format_capture<'v, T: Iterator<Item = Value<'v>>>(
  result: &mut String,
  ) -> anyhow::Result<()> {
  let (n, conv) = {
  - if let Some((n, conv)) = capture.split1_opt('!') {
  + if let Some((n, conv)) = capture.split_once('!') {
  (n, conv)
  } else {
  (capture, "s")
  