Update .arclint in Phabricator for phutil-library lint
Summary:
Also fix a few other minor issues:
- Use lint config.
- Fix a method signature from `arc unit --everything` (unrelated).
- Add a javelin doc.
Test Plan: Ran `arc lint`, `arc unit`, `arc linters`.
Reviewers: btrahan, joshuaspence
Reviewed By: joshuaspence
Subscribers: epriestley
Differential Revision: https://secure.phabricator.com/D9072