doc: update docs to reflect current w3c state of document.hidden flag

[DeepUpRosenthal]

As stated here w3c/page-visibility#64 the .hidden prop is not deprecated.

[github-actions]

Preview URLs

• /en-US/docs/Web/API/Document/hidden

(comment last updated: 2023-05-20 00:22:12)

[estelle]

While not deprecated, {{domxref("Document.visibilityState")}} is a better option and should be recommended. While the statement should be edited, the recommendation/link shouldn't be removed

[DeepUpRosenthal]

I would remove this notice entirely as it is confusing for devs if the prop isn't deprecated. Just my opinion as a dev. I'd put a "See also" section at the bottom of the document where the visibilityState prop page is linked. What do you think?

[teoli2003]

What I would do is to:

• Move the warning in usage notes, where the original note was.
• Transform it into a note and rephrase it a bit to sound more like "Why you should use visibilityState instead of hidden". (Make it more browser-independent.)
• Add a link to visibilityState in the See also section.

What do you think?

[bsmth]

hi @DeepUpRosenthal there's some review comments outstanding on this submission, would you like to take a look? Thank you :)

[wbamberg]

Closing in favour of #29974.