message: Better example in error
diff: @@ -1210,7 +1210,7 @@ impl Config {
  };
  if !ok {
  bail!(
  - "--config argument `{}` was not a TOML dotted key expression (a.b.c = _)",
  + "--config argument `{}` was not a TOML dotted key expression (such as `build.jobs = 2`)",
  arg
  );
  }
  