Move setup warning callout above the nav-drag div
Summary: See T7830: Differential highlighting highlights wrong lines when setup warning is ignored by lackadaisical admins
Test Plan: I manually set this to 5 in Chrome inspector and checked a few pages.
Reviewers: chad, Blessed Reviewers, epriestley
Reviewed By: Blessed Reviewers, epriestley
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D12481