Remove IE-only prefixed APIs

[estelle]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/MediaError/msExtendedCode

What specific section or headline is this issue about?

The page

What information was incorrect, unhelpful, or incomplete?

IE stopped being supported two years ago. Related content can safely be removed.

What did you expect to see?

What i expected NOT to see were these pages:

https://developer.mozilla.org/en-US/docs/Web/API/PerformanceTiming/MsFirstPaint
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/mscandidatewindowhide_event
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/mscandidatewindowshow_event
https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/mscandidatewindowupdate_event
https://developer.mozilla.org/en-US/docs/Web/API/MediaError/msExtendedCode

Do you have any supporting links, references, or citations?

There may be other pages, but these were the ones I identified in a search.

Do you have anything more you want to share?

This issue resolves the https://github.com/orgs/mdn/discussions/620 discussion.