Use actual gitlab.com coordinator URL for suggested one during registration

Closed username-removed-615380 requested to merge spfweb/gitlab-ci-multi-runner:patch-3 into master

This is a general Merge Request template. Consider to choose a template from the list above if it will match your case more.

What does this MR do?

Updates documentation to match actual registration questions

Why was this MR needed?

To reduce confusion - using https://gitlab.com/ for registration fails

Are there points in the code the reviewer needs to double check?

No

Does this MR meet the acceptance criteria?

  • Documentation created/updated
  • Tests
    • [N/A] Added for this feature/bug
    • All builds are passing
  • Branch has no merge conflicts with master (if you do - rebase it please)

What are the relevant issue numbers?

None