Remove obsolete note

[wbamberg]

This came out of https://github.com/mdn/content/discussions/6845 :

For example, "useCapture (of the addEventListener method) has not always been optional", which is false after IE9. These kinds of information are just the source of the confusion to most of the new comers, which only maintain for current browsers.

I agree with this, and this PR removes the note.

[github-actions]

Preview URLs

• https://pr6865.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/EventTarget/addEventListener

Flaws

URL: /en-US/docs/Web/API/EventTarget/addEventListener
Title: EventTarget.addEventListener()
on GitHub
Flaw count: 2

• broken_links:
  • Is currently http:// but can become https://
  • Is currently http:// but can become https://

External URLs

URL: /en-US/docs/Web/API/EventTarget/addEventListener
Title: EventTarget.addEventListener()
on GitHub

• https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md (1 time)
• https://github.com/rafrex/detect-it (1 time)
• https://modernizr.com/docs (1 time)
• https://wicg.github.io/admin/charter.html (1 time)
• https://www.quirksmode.org/js/events_order.html (1 time)
• https://www.quirksmode.org/js/this.html (1 time)
• https://www.w3.org/TR/DOM-Level-2-Events (1 time)
• https://www.w3.org/TR/DOM-Level-3-Events/ (1 time)