Some tweaks to [27106]:

* Add more @todo markings and remove one that's been resolved.
* Restore a missing comma in a `.wp-badge` background rule, and add a comment reminding us why it's there.

see #18380.

Built from https://develop.svn.wordpress.org/trunk@27107


git-svn-id: https://core.svn.wordpress.org/trunk@26974 1a063a9b-81f0-0310-95a4-ce76da25c4cd