message: Unnecessary string allocation in chr function
diff: @@ -211,10 +211,10 @@ pub(crate) fn global_functions(builder: &mut GlobalsBuilder) {
  #[starlark(speculative_exec_safe)]
  fn chr(
  #[starlark(require = pos, type = "[int.type, bool.type]")] i: Value,
  - ) -> anyhow::Result<String> {
  + ) -> anyhow::Result<char> {
  let cp = i.to_int()? as u32;
  match std::char::from_u32(cp) {
  - Some(x) => Ok(x.to_string()),
  + Some(x) => Ok(x),
  None => Err(anyhow::anyhow!(
  "chr() parameter value is 0x{:x} which is not a valid UTF-8 codepoint",
  cp
  