Post formats should show_in_nav_menus when the current theme supports them....

Post formats should show_in_nav_menus when the current theme supports them. Props filosofo, nacin. Fixes #16390.


git-svn-id: https://core.svn.wordpress.org/trunk@19876 1a063a9b-81f0-0310-95a4-ce76da25c4cd