Allow the API to add text to auto update emails.

fixes #27812.


git-svn-id: https://develop.svn.wordpress.org/trunk@28134 602fd350-edb4-49c9-b593-d223f7449a82
3.9-RC2


git-svn-id: https://develop.svn.wordpress.org/trunk@28135 602fd350-edb4-49c9-b593-d223f7449a82