R1:59b95f939780

Fix typo in "button"

Test Plan: Observation.

Reviewers: #blessed_reviewers, amckinley, epriestley

Reviewed By: #blessed_reviewers, amckinley, epriestley

Subscribers: Korvin, amckinley, epriestley

Differential Revision: https://secure.phabricator.com/D19483