Add support for ".woff2" resources

Summary: Ref T7210. Not sure if this fixes things, but it's definitely an issue.

Test Plan:

• Not able to reproduce issue locally yet.
• These get into the map now, at least?
• Saw .woff2 URIs transform in CSS.
• Loaded a .woff2 file.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T7210

Differential Revision: https://secure.phabricator.com/D11720