Fix a typo on Almanac User Guide
The lack of a * messed up the remarkup.
Tested on my instance by pasting the sentence in a phriction document.
See the markup correctly done.
Reviewers: epriestley, Blessed Reviewers
Reviewed By: epriestley, Blessed Reviewers
Maniphest Tasks: T10527
Differential Revision: https://secure.phabricator.com/D15421