Summary:
Fixes T12461. This returns the field as a dictionary with a `"raw"` value, so we could eventually do this if we want without breaking the API:

```
{
  "type": "remarkup",
  "raw": "**raw**",
  "html": "<strong>raw</strong>",
  "text": "raw"
}
```

Test Plan: Called `maniphest.search`, reviewed output.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12461

Differential Revision: https://secure.phabricator.com/D17603