[go sdk] update documentation
The documentation at
refers to the old Go SDK. The godoc link for the go/sdk/arvados directory describes the current SDK. We want to move over to an RPC interface as per #18672.
- The godoc should be updated/improved to incorporate all the examples from the examples page at our documentation site.
- Examples should be added for important features (e.g. the CollectionFileSystem)
- The old pages should be removed from the Arvados documentation, with only the godoc link remaining. Any Go programmer should be able to use the Arvados Go sdk with just the godoc page.