check for broken links
check for broken links

Seeing [a number of issues around broken links in the docs](https://github.com/docker/docker.github.io/issues?q=is%3Aissue+is%3Aopen+broken+link); this should help avoid the issue.
docker/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io