dir, lang, and xml:lang should be global attributes supported on all tags

[upsuper]

Currently in kses, dir, lang, and xml:lang are only supported in several selected elements, however, as can be found in the ​HTML standard, they are all global attributes and can be applied to any element.

It doesn't make sense, for example, to have to write <span lang="ja"><em>こんにちは</em></span> while you can pretty much just use <em lang="ja">こんにちは</em>.

This PR moves dir, lang, and xml:lang attributes into the global attributes in kses so that they can be used with any tag as specified in the HTML standard.

Trac ticket: https://core.trac.wordpress.org/ticket/54699

[mukesh27]

Hi there!

Thanks for the ticket and patch!

In the PR we should add document for _wp_add_global_attributes() function. Something like:

* @since 6.0.0 Add global support for `dir`, `lang`, and `xml:lang` attributes.

[upsuper]

Updated the PR to include that item.

Trac ticket: https://core.trac.wordpress.org/ticket/54699

[audrasjb]

I added a PR to refresh the patch and to add forgotten items.

[audrasjb]

@SergeyBiryukov would you mind reviewing the above PR please?
I think we're good, but just want to double check before shipping this change.

[upsuper]

Any update here?

[audrasjb]

Hello @upsuper, thanks for the heads up.
I think we're good to go.
I self assigned the ticket but I'm only waiting for another committer review before shipping it to milestone 6.0.

Thanks for the refreshed PR! This looks good to me, just added some more WPCS fixes and formatting adjustments.

Superseded by #2193

[peterwilsoncc]

In 52968:

KSES: Allow lang, xml:lang, dir attributes globally.

Globally permit the lang, xml:lang, and dir attributes on all elements rather than a subset in accordance with the HTML specification.

Props upsuper, SergeyBiryukov, mukesh27, audrasjb.
Fixes #54699.

Committed in e7a9f9df4e13b94187ea362f55ddfdaa0f6911f3 (canonically https://core.trac.wordpress.org/changeset/52968)