Add links to our lovely new Help repo
Link to Docs should always be 'Docs'. Props @cobyism
Shorten 'Overview' to 'Home'
Redirect all the people to the help repo.
With 5 items in the main navigation, limit the width to 20% rather than 25%.
Restore 'Documentation' ~> 'Docs' because long words are fun.
Merge pull request #2177 from jekyll/help