Make some strings in ArcanistPhutilXHPASTLinter translatable

Summary: phtize some string in ArcanistPhutilXHPASTLinter so that they are translatable.

Test Plan: Not 100% sure that I am doing it right...

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D10431