R1:2b7ec1deea31

Boost search result title matches

Summary: Ref T6740. When a query matches a document title, boost results.

Test Plan:
- Searched for `button bar`.
- Before:

{F2019463}

- After:

{F2019470}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T6740

Differential Revision: https://secure.phabricator.com/D16945