Apply various linter fixes.

Summary: Applied various linter fixes. Also make the .editorconfig file a bit more specific. Unfortunately, arc lint --apply-patches currently modifies some test data that it shouldn't, but this should be fixed after T5105.

Test Plan: Ran arc unit to make sure things weren't broken.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin, aurelijus

Differential Revision: https://secure.phabricator.com/D9440