LibJS+LibWeb: Remove remaining use and reference to SafeFunction

Author: https://github.com/shannonbooth
Commit: 797b0d0f43
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2062
Reviewed-by: https://github.com/kalenikaliaksandr ✅

Userland/Libraries/LibWeb/DOM/EventTarget.cpp

@@ -197,7 +197,7 @@ void EventTarget::add_an_event_listener(DOMEventListener& listener)
 
     // 5. If listener’s signal is not null, then add the following abort steps to it:
     if (listener.signal) {
-        // NOTE: `this` and `listener` are protected by AbortSignal using JS::SafeFunction.
+        // NOTE: `this` and `listener` are protected by AbortSignal using JS::HeapFunction.
         listener.signal->add_abort_algorithm([this, &listener] {
             // 1. Remove an event listener with eventTarget and listener.
             remove_an_event_listener(listener);