add some comments

text2world_hf.py

@@ -123,6 +123,7 @@ class DiffusionText2World(PreTrainedModel):
 
     @classmethod
     def from_pretrained(cls, pretrained_model_name_or_path, *model_args, **kwargs):
+        # TODO: this only builds the class, but not download the checkpoints.
         config = kwargs["config"]
         model = cls(config)
         return model