Gitpod: Enable docs by default

What does this Merge Request do and why?

Follow-up from: gitlab!73916 (merged).

If we set the docs by default at this stage, startup will be likely a little quicker because we don't need to pull all of the docs and it's dependencies.

Merge Request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise Issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.