docs: GcrViewerWindow shouldn't be in the documentation types
docs: GcrViewerWindow shouldn't be in the documentation types

Since it's not public API, at least not yet.

stefwalter/gcr,Distrotech/gcr,Distrotech/gcr,Distrotech/gcr,stefwalter/gcr,Distrotech/gcr,stefwalter/gcr,stefwalter/gcr