LibWeb: Begin detecting the end of an HTMLMediaElement media resource

Author: https://github.com/trflynn89
Commit: 4797f07883
Pull-request: https://github.com/SerenityOS/serenity/pull/18281
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWeb/HTML/HTMLMediaElement.idl

@@ -33,6 +33,7 @@ interface HTMLMediaElement : HTMLElement {
     attribute double currentTime;
     readonly attribute unrestricted double duration;
     readonly attribute boolean paused;
+    readonly attribute boolean ended;
     [Reflect, CEReactions] attribute boolean autoplay;
     [Reflect, CEReactions] attribute boolean loop;
     Promise<undefined> play();