Fixes #686 - makes short desc optional

- Fixes #686 - short description was assumed to be present, however, it
is no longer necessarily present. This commit makes the short
description partial content only present when `short_desc` has a value.
- Updates test to check for updated text in translate spec.
Merge pull request #700 from codeforamerica/686-desc-whitespace

Fixes #686 - makes short desc optional