Added doc strings to wandb logger (#9109)

Author: bamblebam

pytorch_lightning/loggers/wandb.py

@@ -219,15 +219,33 @@ def log_metrics(self, metrics: Dict[str, float], step: Optional[int] = None) ->
 
     @property
     def save_dir(self) -> Optional[str]:
+        """
+        Gets the save directory.
+
+        Returns:
+            The path to the save directory.
+        """
         return self._save_dir
 
     @property
     def name(self) -> Optional[str]:
+        """
+        Gets the name of the experiment.
+
+        Returns:
+            The name of the experiment if the experiment exists else the name given to the constructor.
+        """
         # don't create an experiment if we don't have one
         return self._experiment.project_name() if self._experiment else self._name
 
     @property
     def version(self) -> Optional[str]:
+        """
+        Gets the id of the experiment.
+
+        Returns:
+            The id of the experiment if the experiment exists else the id given to the constructor.
+        """
         # don't create an experiment if we don't have one
         return self._experiment.id if self._experiment else self._id