Adds a method to elements to get their event listeners
Adds a listEventListeners method to every element that returns an array containing every event added to that listener.
A quick example:
const el = document.getElementById("my-test-element");
el.addEventListener("click", doSomething);
el.listEventListeners(); // returns {"click":[doSomething]}
el.listEventListeners("click"); // returns [doSomething]