Update the GitLab Pages documentation to reference "gitlab.io" as the domain name for gitlab.com users
The documentation for GitLab Pages (http://doc.gitlab.com/ee/pages/README.html) is currently written entirely from the perspective of a user who self-hosts GitLab EE on their own server. The table of patterns for repository name and URL schema only talks about a custom domain being used (e.g. "example.com").
It would be great for this documentation to include a section for GitLab.com SaaS users (perhaps in between the "Understanding how GitLab Pages work" and the "Group pages" H2's). This may sound silly, but I had a very frustrating experience getting starting before I realized that "gitlab.io" rather than "gitlab.com" is the domain name used for GitLab.com SaaS page hosting. There no mention of that domain name in the documentation, and unfortunately GitLab Pages are not yet ubiquitous enough that "everyone just knows that".
I believe that burying a mention of "gitlab.io" in the middle of paragraph text would be too easy to miss, and that this should be an H2 section in its own right. However, the SaaS-specific section really doesn't need to say anything other than the fact that "github.io" is the hosted name for GitLab.com SaaS pages. If you add more features to the SaaS product (e.g. custom domain names), then the section could expand later.
I'm happy to submit a proposed change myself, if you add an "Accepting merge requests" tag to this issue. However, following the Contribution Guidelines it seemed best to submit an issue first. Thanks!