events: clarify JSDoc entries

Split the JSDoc entries into separate blocks.

This is in preparation for enabling jsdoc/check-param-names lint rule.

PR-URL: nodejs#41311
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/event_target.js

@@ -443,7 +443,13 @@ class EventTarget {
   /**
    * @callback EventTargetCallback
    * @param {Event} event
+   */
+
+  /**
    * @typedef {{ handleEvent: EventTargetCallback }} EventListener
+   */
+
+  /**
    * @param {string} type
    * @param {EventTargetCallback|EventListener} listener
    * @param {{