R1:cb4add311649

In Ferret, allow documents with no title to match query terms by using LEFT JOIN on the "title" ranking field

Summary:
Fixes T13345. See D20650. Currently, `PhabricatorCursorPagedPolicyAwareQuery` does a JOIN against the "title" field so it can apply additional ranking/ordering conditions to the query.

This means that documents with no title (which don't have this field) are always excluded from the result set.

We'd prefer to include them, just not give them any bonus ranking/relevance boost. Use a LEFT…