WP_Date_Query: The inclusive logic should include all times within the date range.

props mboynes, oso96_2000, DrewAPicture.
fixes #26653.
Built from https://develop.svn.wordpress.org/trunk@28935


git-svn-id: http://core.svn.wordpress.org/trunk@28733 1a063a9b-81f0-0310-95a4-ce76da25c4cd
General inline documentation improvements in wp-includes/functions.php.

Second run. See #26185.

Built from https://develop.svn.wordpress.org/trunk@28936


git-svn-id: http://core.svn.wordpress.org/trunk@28734 1a063a9b-81f0-0310-95a4-ce76da25c4cd