phpdoc improvements for wp_dashboard_quota()

Props DrewAPicture, h4ck3rm1k3


git-svn-id: http://core.svn.wordpress.org/trunk@24246 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove obsolete TODO.

Props wonderboymusic
fixes #11635


git-svn-id: http://core.svn.wordpress.org/trunk@24247 1a063a9b-81f0-0310-95a4-ce76da25c4cd