The help output prints the first line of the doc string.

Change-Id: I76817d5138b7bb7ba8034c6a5d803b5aaf1201f7
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/654603Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47871}