Update developer.wordpress.org/reference with changes from 6.8

[jorbin]

It seems as though the parsing of docs for 6.8 either didn't complete fully or didn't complete sucessfully. Two specifics that make me think this is an issue:

• I don't see ​https://developer.wordpress.org/reference/functions/is_post_embeddable/ which is a new function

• ​https://developer.wordpress.org/reference/functions/get_post_type_labels/ isn't updated with the new defaults for add_new_item and add_new

[dd32]

Merging this with #7963 - I suspect it's an issue in the phpdoc-parser + PHP 8.1

[dd32]

This is subtly different..

[dd32]

Reimported the 6.8 changes.

It seems that the import that was run for 6.8 was either incomplete, or wasn't run with the proper source checkout.

The PHPDoc parser we use can no longer be run on WordPress.org, as such, it can't be imported directly into developer.w.org and must be run locally on a PHP7 install first, and then exported / uploaded, and then a separate task run to import the code examples..

Filed (and rambled) about the compatility issues in ​https://github.com/WordPress/phpdoc-parser/issues/246