message: Fix up config_include test
diff: @@ -274,9 +274,14 @@ fn cli_path() {
  assert_error(
  config.unwrap_err(),
  "\
  -failed to parse --config argument `missing.toml`
  +failed to parse value from --config argument `missing.toml` as a dotted key expression
  Caused by:
  - expected an equals, found eof at line 1 column 13",
  + TOML parse error at line 1, column 13
  + |
  +1 | missing.toml
  + | ^
  +Unexpected `end of input`
  +Expected `.` or `=`",
  );
  }
  