insertAfterNode(ref) {
        this.startNode = ref;
        this.endNode = ref.nextSibling;
    }
Inserts this part between `ref` and `ref`'s next sibling. Both `ref` and
its next sibling must be static, unchanging nodes such as those that appear
in a literal section of a template.

This part must be empty, as its contents are not automatically moved.