Set date format before going into the loop to avoid a PHP notice if 'lastupdated' column is filtered out.

props jeremyfelt.
fixes #27614.
Built from https://develop.svn.wordpress.org/trunk@28898


git-svn-id: http://core.svn.wordpress.org/trunk@28697 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Re-document default arguments in `wp_link_pages()` using the hash-notation style.

Props taylorde.
Fixes #28680.

Built from https://develop.svn.wordpress.org/trunk@28899


git-svn-id: http://core.svn.wordpress.org/trunk@28698 1a063a9b-81f0-0310-95a4-ce76da25c4cd