Add some missing function parameter typehints

Summary: Add some missing function parameter typehints to the `ArcanistPhutilXHPASTLinter` class.

Test Plan: Eyeball it.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D10430