Ensure that a space is used after a catch token
Summary: For consistency, a single space should separate catch and the following parenthetical expression.
Test Plan: Added test case.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: epriestley, Korvin
Differential Revision: https://secure.phabricator.com/D13389