R1:aaa81b48349d

Center Pager buttons

Summary: Fixes T12305. Centers the buttons, which I prefer anyways.

Test Plan: Review buttons, now centered.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12305

Differential Revision: https://secure.phabricator.com/D17394