Minor fixes for `.arclint` file

Summary:
Minor fixes for the `.arclint` file. Specifically:

- Don't explicitly lint excluded paths (they are already excluded globally)
- Set the `xhpast.php-version` and `xhpast.php-version.windows` configuration (this should have been done in D9593, but wasn't)
- Sort `.arclint` linters alpahbetically

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9803