Expand typeahead document copy

Summary: Seems reasonable? At least, it always matches however a user might think about documents (app or document). Unclear if "Diffusion" for example, are actually needed.

Test Plan: tested searching for "phriction", "wiki", "document", etc.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12577