making litmodels message clearer (#20707)

* making litmodels message clearer

* linter

---------

Co-authored-by: Jirka B <j.borovec+github@gmail.com>

Author: craigpfeifer

src/lightning/pytorch/trainer/connectors/callback_connector.py

@@ -106,8 +106,9 @@ def _configure_checkpoint_callbacks(self, enable_checkpointing: bool) -> None:
                 model_checkpoint = LitModelCheckpoint(model_name=self.trainer._model_registry)
             else:
                 rank_zero_info(
-                    "You are using the plain ModelCheckpoint callback."
-                    " Consider using LitModelCheckpoint which with seamless uploading to Model registry."
+                    "You are using the default ModelCheckpoint callback."
+                    " Install `litmodels` package to use the `LitModelCheckpoint` instead"
+                    " for seamless uploading to the Lightning model registry."
                 )
                 model_checkpoint = ModelCheckpoint()
             self.trainer.callbacks.append(model_checkpoint)