Merge branch 'help-page-dark' into 'master'

Render "Enterprise Edition" on help page with dark font.

Addresses internal issue https://dev.gitlab.org/gitlab/gitlab-ee/issues/284.

See merge request !3

app/views/help/index.html.haml

 %div
   %h1
     GitLab
-    %span.light Enterprise Edition
+    Enterprise Edition
     %span= Gitlab::VERSION
     %small= Gitlab::REVISION
     - if current_application_settings.version_check_enabled