[docs] Update docstrings for PostProcessing

src/bayesvalidrox/post_processing/post_processing.py

@@ -228,13 +228,6 @@ class PostProcessing:
         Exception
             When neither n_samples nor samples are provided.
 
-        Returns
-        -------
-        rmse: dict
-            Root mean squared error for each output.
-        valid_error : dict
-            Validation error for each output.
-
         """
         # Set the number of samples
         if n_samples: