message: Relax some rustdoc tests.
diff: @@ -1372,7 +1372,7 @@ fn doc_message_format() {
  p.cargo("doc --message-format=json")
  .with_status(101)
  - .with_json(
  + .with_json_contains_unordered(
  r#"
  {
  "message": {
  @@ -1402,10 +1402,7 @@ fn short_message_format() {
  p.cargo("doc --message-format=short")
  .with_status(101)
  .with_stderr_contains(
  - "\
  -src/lib.rs:4:6: error: `[bad_link]` cannot be resolved, ignoring it...
  -error: Could not document `foo`.
  -",
  + "src/lib.rs:4:6: error: `[bad_link]` cannot be resolved, ignoring it...",
  )
  .run();
  }
  