message: Go: Add some more detail to an error message.
  Closes
diff: @@ -270,7 +270,7 @@ func typeOf(dt DataType, shape []int64) reflect.Type {
  }
  }
  if ret == nil {
  - panic(bug("DataType %v is not supported", dt))
  + panic(bug("DataType %v is not supported (see https://www.tensorflow.org/code/tensorflow/core/framework/types.proto)", dt))
  }
  for range shape {
  ret = reflect.SliceOf(ret)
  