Docs: follow up from "Clearly state web terminal is not supported at all on GitLab.com"

What does this MR do?

• Correct changes introduced by https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8849
• Perform direct review
• CE MR: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23821

Related issues

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/8866

Author's checklist

• Apply the correct labels and milestone
• Correctly apply the product badges and tiers

Review checklist

• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge this first, CE-MR afterwards (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23821)