message: Avoid re-parsing config-cli toml
diff: @@ -1215,9 +1215,7 @@ impl Config {
  );
  }
  - // Rather than trying to bridge between toml_edit::Document and toml::Value, we
  - // just parse the whole argument again now that we know it has the right format.
  - let toml_v = toml::from_str(arg).with_context(|| {
  + let toml_v = toml::from_document(doc).with_context(|| {
  format!("failed to parse value from --config argument `{}`", arg)
  })?;
  