Fix scrolling behavior in Diffusion

Summary: Fixes T7084. This doesn't use the same anchor logic as other applications.

Test Plan: $245 lines now jump to line 245 on page load.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T7084

Differential Revision: https://secure.phabricator.com/D11563