Update a few links in the Leadership section. (!30904) · Merge requests · GitLab.com / www-gitlab-com · GitLab

Brian Sexton requested to merge update-abs-links-leadership into master Sep 26, 2019

This updates a few links in the Leadership section of the Handbook.

It changes "merging the CE and EE codebases" to "merged the CE and EE codebases" at https://about.gitlab.com/handbook/leadership/biggest-risks/#operational-excellence.
It makes a few same-site links root-relative.
It fixes a couple minor typos.