R1:205ddcf13424

Fix header anchor colors

Summary: I inadvertantly removed this rule and I am very fond of it.

Test Plan: Browse history in Diffusion, header links are dark again

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7714