R1:b90e02bec287

Select Ferret fulltext columns in results so fulltext queries work under UNION

Summary:
Ref T13091. In Differential, if you provide a query and "Sort by: Relevance", we build a query like this:

```
((SELECT revision.* FROM ... ORDER BY rank) UNION ALL (SELECT revision.* FROM ... ORDER BY rank)) ORDER BY rank
```

The internal "ORDER BY rank" is technically redundant (probably?), but doesn't hurt anything, and makes construction easier.

The problem is that the outer "ORDER BY rank" at the end, which…