script: Move code generation and webidl files to new script_bindings crate. (#35157)

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

components/script_bindings/webidls/HTMLSlotElement.webidl

@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#the-slot-element
+[Exposed=Window]
+interface HTMLSlotElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
+  [CEReactions] attribute DOMString name;
+  sequence<Node> assignedNodes(optional AssignedNodesOptions options = {});
+  sequence<Element> assignedElements(optional AssignedNodesOptions options = {});
+  undefined assign((Element or Text)... nodes);
+};
+
+dictionary AssignedNodesOptions {
+  boolean flatten = false;
+};
+
+// https://dom.spec.whatwg.org/#mixin-slotable
+interface mixin Slottable {
+  readonly attribute HTMLSlotElement? assignedSlot;
+};
+Element includes Slottable;
+Text includes Slottable;