R1:8b15d1928d6e

Use JX.DOM everywhere in behavior-dropdown

Summary: see title

Test Plan: Tested locally. Noticed same number replacement and bold/unbold text as before.

Reviewers: epriestley

Reviewed By: epriestley

CC: allenjohnashton, keebuhm, aran, Korvin, David

Differential Revision: https://secure.phabricator.com/D2720