Summary: Using `##` can cause some formatting issues, see D13071.
Test Plan: See D13071.
Reviewers: epriestley, #blessed_reviewers, chad
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D13072
Summary: ...and fix an error where lines that start with ##X## are rendering incorrectly by switching to alternate syntax `X`. Fixes T5806.
Test Plan: read the docs and they looked good
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T5806
Differential Revision: https://secure.phabricator.com/D10165