Currently our docs include the GAPIC generated stubs and protobuf documentation. Unfortunately the GAPIC stubs (ie v2.BigtableClient) do not provide enough functionality to use bigtable correctly (it lacks row merging and proper retries).
It is also unclear to me how much of the autogenerated types are used on the public surface. Ideally any types that aren't used on the public surface should be removed from the autogenerated docs.