R1:b3ca73ff1baf

Fix subscribers in PHUIDocument

Summary: This resolves a wrapping issue in phui-document-css

Test Plan: reload page, subscribers no longer wrap.

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7301