[META] Ensure CKE5 equivalent plugins of CKE4 generate/support equivalent markup

Thanks to #3216015-14: Generate CKEditor 5 configuration based on pre-existing text format configuration it just became super easy to finish this.

For basic_html these remain in current HEAD (a2dcccd3901d6d10138e642e73dc30aac88d4188):

• The following tags were permitted by this format's filter configuration, but no plugin is available that supports them: <cite> <dl> <dt> <dd>
• The following tags are enabled, but no plugin was found that could support certain attributes configured in this format's HTML filters: <ul type> <ol start type> <h2 id> <h3 id> <h4 id> <h5 id> <h6 id> <img height width> 

For restricted_html these remain:

• The following tags were permitted by this format's filter configuration, but no plugin is available that supports them: <cite> <dl> <dt> <dd>
• The following tags are enabled, but no plugin was found that could support certain attributes configured in this format's HTML filters: <ul type> <ol start type> <h2 id> <h3 id> <h4 id> <h5 id> <h6 id>

The only thing in there that does not already have an issue is <h2 id> <h3 id> <h4 id> <h5 id> <h6 id>, or IOW the ability to assign an anchor to a heading.

Created #3224256: <h* id> (or more generically: <$block id>) for that.

If I compare the list of remaining HTML tags+attributes here with what's in Drupal 8|9's core/assets/vendor/ckeditor/build-config.js, this is AFAICT complete 👍

And 100% of the remaining tags/attributes could only be entered using CKEditor 4's View Source button. So we're not regressing functionality-wise compared to CKEditor 4! 🎉

Closing this per #3201824-20: Roadmap to core.