Applying (user )?monospace font to remarkup code blocks

Summary:
I feel that remarkup code blocks are still kind of small. This should help with my reading problems. Hesitating to add .PhabricatorMonospaced to the remarkup rule, since it's pretty specific to Phabricator.

Pasting in the diff btw, since my arc's going crazy (doubt that's arc.exe, since it's not landed yet).

Test Plan:
Set font to something large. viewed code block. Was not large.

Applied change. Viewed code block again. It was HUGE!

Also verified that the init.js was still there. I think that's the one being inserted $5.

Reviewers: epriestley, chad

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5727