kiji-express: EXP-320. Fix up scaladocs for input options.

issue: https://jira.kiji.org/browse/EXP-320
review: https://review.kiji.org/r/1408/
commit: https://github.com/kijiproject/kiji-express/commit/5898d4375fbd7d1f6bc48cd550e9a112eddecad9