Allow callback args to be passed from wp_add_dashboard_widget() to add_meta_box().

props jdgrimes.
fixes #25152.

Built from https://develop.svn.wordpress.org/trunk@25454


git-svn-id: http://core.svn.wordpress.org/trunk@25375 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Inline documentation for hooks in wp-includes/load.php.

props mordauk.
see #25229.
Built from https://develop.svn.wordpress.org/trunk@25455


git-svn-id: http://core.svn.wordpress.org/trunk@25376 1a063a9b-81f0-0310-95a4-ce76da25c4cd