Change double quotes to single quotes.
Summary: Ran arc lint --apply-patches --everything over rP, mainly to change double quotes to single quotes where appropriate. These changes also validate that the ArcanistXHPASTLinter::LINT_DOUBLE_QUOTE rule is working as expected.
Test Plan: Eyeballed it.
Reviewers: Blessed Reviewers, epriestley
Reviewed By: Blessed Reviewers, epriestley
Subscribers: epriestley, Korvin, hach-que
Differential Revision: https://secure.phabricator.com/D9431