Inline documentation for hooks in wp-admin/user-new.php & wp-admin/user-edit.php.

Also fixes one parameter type in wp-includes/user.php.

Fixes #25726.

Built from https://develop.svn.wordpress.org/trunk@26493


git-svn-id: http://core.svn.wordpress.org/trunk@26387 1a063a9b-81f0-0310-95a4-ce76da25c4cd