fix typo

pts/dataset/multivariate_grouper.py

@@ -204,3 +204,4 @@ class MultivariateGrouper:
                 freq=data[FieldName.START].freq,
             ),
         )
+ 

pts/model/estimator.py

@@ -108,7 +108,7 @@ class PTSEstimator(Estimator):
         )
 
         training_data_loader = DataLoader(
-            traning_iter_dataset,
+            training_iter_dataset,
             batch_size=self.trainer.batch_size,
             num_workers=self.train.num_workers,
             pip_memory=self.trainer.pip_memory