Update progress_bar_metrics return _PBAR_DICT

Author: Jungwon-Lee

src/pytorch_lightning/callbacks/progress/base.py

@@ -222,7 +222,7 @@ def setup(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule", stage: O
         if not trainer.is_global_zero:
             self.disable()
 
-    def get_metrics(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> Dict[str, Union[int, str]]:
+    def get_metrics(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> Dict[str, Union[int, str, float, Dict[str, float]]]:
         r"""
         Combines progress bar metrics collected from the trainer with standard metrics from get_standard_metrics.
         Implement this to override the items displayed in the progress bar.

src/pytorch_lightning/trainer/trainer.py

@@ -77,7 +77,7 @@
 from pytorch_lightning.trainer.connectors.checkpoint_connector import CheckpointConnector
 from pytorch_lightning.trainer.connectors.data_connector import DataConnector
 from pytorch_lightning.trainer.connectors.logger_connector import LoggerConnector
-from pytorch_lightning.trainer.connectors.logger_connector.result import _OUT_DICT, _ResultCollection
+from pytorch_lightning.trainer.connectors.logger_connector.result import _OUT_DICT, _PBAR_DICT, _ResultCollection
 from pytorch_lightning.trainer.connectors.signal_connector import SignalConnector
 from pytorch_lightning.trainer.data_loading import TrainerDataLoadingMixin
 from pytorch_lightning.trainer.optimizers import TrainerOptimizersMixin
@@ -2735,7 +2735,7 @@ def logged_metrics(self) -> _OUT_DICT:
         return self._logger_connector.logged_metrics
 
     @property
-    def progress_bar_metrics(self) -> Dict:
+    def progress_bar_metrics(self) -> _PBAR_DICT:
         return self._logger_connector.progress_bar_metrics
 
     @property