1. "blob" is not a "ref", it shouldn't (and not unable to) be handled by
`RepoRefByType`
2. the `/blob/{sha}` handle should use the path param "sha" directly
1. "blob" is not a "ref", it shouldn't (and not unable to) be handled by
`RepoRefByType`
2. the `/blob/{sha}` handle should use the path param "sha" directly