try fixing doc build

Author: SkafteNicki

src/lightning/pytorch/loggers/tensorboard.py

@@ -274,11 +274,17 @@ def _get_next_version(self) -> int:
     @override
     @rank_zero_experiment
     def experiment(self) -> "SummaryWriter":
-        """Returns the underlying TensorBoard summary writer object. Allows you to use TensorBoard logging features
-        directly in your :class:`~lightning.pytorch.core.LightningModule` or anywhere else in your code with:
+        """Returns the underlying TensorBoard summary writer object.
+
+        Allows you to use TensorBoard logging features directly in your
+        :class:`~lightning.pytorch.core.LightningModule` or anywhere else in your code with:
 
         `logger.experiment.some_tensorboard_function()`
 
+        Returns:
+            The :class:`torch.utils.tensorboard.SummaryWriter` or :class:`tensorboardX.SummaryWriter`
+            depending on which is available.
+
         Example::
 
             class LitModel(LightningModule):