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.


git-svn-id: https://develop.svn.wordpress.org/trunk@27107 602fd350-edb4-49c9-b593-d223f7449a82