Now `#[dom_struct]` also generates Reflectable impls, and there's another lint to ensure that a DOM struct only contains one bare DOM field (as the first field) or a Reflector.
A lot of this was generated by sed -- each autogenerated change has its own commit for easy review; these will be squashed later.
Source-Repo: https://github.com/servo/servo
Source-Revision: 56d1b16d1b3a18d5ffa1d9c32562d3b209851711
