script: Change signature of Event::dispatch to match the spec and simplify things (#38566)

- [Dispatch Event](https://dom.spec.whatwg.org/#concept-event-dispatch)
should return a Boolean. This function is used frequently in spec and
the change makes things easier to follow.
- Remove `enum EventStatus` and related functions.
- Update some dead spec link.
- Update some steps.

This is intended as cleanup before working on #38435 and reduces binary
size by 488KB in Release profile.

Testing: No behaviour change.

---------

Signed-off-by: Euclid Ye <euclid.ye@huawei.com>

components/script/dom/window.rs

@@ -130,7 +130,7 @@ use crate::dom::cssstyledeclaration::{CSSModificationAccess, CSSStyleDeclaration
 use crate::dom::customelementregistry::CustomElementRegistry;
 use crate::dom::document::{AnimationFrameCallback, Document};
 use crate::dom::element::Element;
-use crate::dom::event::{Event, EventBubbles, EventCancelable, EventStatus};
+use crate::dom::event::{Event, EventBubbles, EventCancelable};
 use crate::dom::eventtarget::EventTarget;
 use crate::dom::gamepad::{Gamepad, contains_user_gesture};
 use crate::dom::gamepadevent::GamepadEventType;
@@ -705,12 +705,8 @@ impl Window {
     }
 
     // see note at https://dom.spec.whatwg.org/#concept-event-dispatch step 2
-    pub(crate) fn dispatch_event_with_target_override(
-        &self,
-        event: &Event,
-        can_gc: CanGc,
-    ) -> EventStatus {
-        event.dispatch(self.upcast(), true, can_gc)
+    pub(crate) fn dispatch_event_with_target_override(&self, event: &Event, can_gc: CanGc) {
+        event.dispatch(self.upcast(), true, can_gc);
     }
 
     pub(crate) fn font_context(&self) -> &Arc<FontContext> {