Aesthetic tweaks to sheriff-o-matic.

The only functional difference is that we no longer repeat the
step name on every line. Otherwise, it's all CSS tweaks.

NOTRY=true
R=michaelpg@chromium.org

Review URL: https://codereview.chromium.org/553343002

git-svn-id: svn://svn.chromium.org/blink/trunk@181789 bbb929c8-8fbe-4397-9dbb-9b2b20218538