Automattic/jetpack — pull request #284 by RsrchBoy (2014-03-01 05:29:03+00:00)
Title: use content, attribute 0 -or- 'id'

There are a number of other gist-shortcode-providing plugins out there, almost
all of which use the 'id' attribute. This change honors that attribute as
well, to allow for an easy migration.