script-servo is broken again

[nnethercote]

Buried among the many warnings is this error:

error[E0599]: no method named `trace` found for type `&for<\'r> fn(&\'r dom::node::Node) -> u16` in the current scope
   --> components/script/dom/treewalker.rs:470:10
    |
470 | #[derive(JSTraceable)]
    |          ^^^^^^^^^^^
    |
    = note: JSTraceable is a function, perhaps you wish to call it
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `trace`, perhaps you need to implement it:
            candidate #1: `dom::bindings::trace::JSTraceable`

[SimonSapin]

This sounds related to rust-lang/rust#56105. Did the breakage occur when rust-lang/rust#58592 landed?

The fix might be adding an impl, similar to servo/servo#18327.

[nnethercote]

I removed an impl like that in #289 just last week. The conversation on IRC said the universes change was backed out, so seems like this is fallout from all that.

[nnethercote]

I pushed a fix for this.