Alphabetize `.arclint` linters

Summary: I'm a bit OCD with this, but I find the `.arclint` file easier to read if the keys are in alphabetical order.

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9804