Doc styling fixes (#8074)

* Fix a few docstrings

* More fixes

* Styling

src/transformers/trainer.py

@@ -194,18 +194,21 @@ class Trainer:
 
             The function may have zero argument, or a single one containing the optuna/Ray Tune trial object, to be
             able to choose different architectures according to hyper parameters (such as layer count, sizes of inner
-            layers, dropout probabilities etc). compute_metrics (:obj:`Callable[[EvalPrediction], Dict]`, `optional`):
+            layers, dropout probabilities etc).
+        compute_metrics (:obj:`Callable[[EvalPrediction], Dict]`, `optional`):
             The function that will be used to compute metrics at evaluation. Must take a
-            :class:`~transformers.EvalPrediction` and return a dictionary string to metric values. callbacks (List of
-            :obj:`~transformers.TrainerCallback`, `optional`): A list of callbacks to customize the training loop. Will
-            add those to the list of default callbacks detailed in :doc:`here <callback>`.
+            :class:`~transformers.EvalPrediction` and return a dictionary string to metric values.
+        callbacks (List of :obj:`~transformers.TrainerCallback`, `optional`):
+            A list of callbacks to customize the training loop. Will add those to the list of default callbacks
+            detailed in :doc:`here <callback>`.
 
             If you want to remove one of the default callbacks used, use the :meth:`Trainer.remove_callback` method.
-            optimizers (:obj:`Tuple[torch.optim.Optimizer, torch.optim.lr_scheduler.LambdaLR`, `optional`): A tuple
+        optimizers (:obj:`Tuple[torch.optim.Optimizer, torch.optim.lr_scheduler.LambdaLR`, `optional`): A tuple
             containing the optimizer and the scheduler to use. Will default to an instance of
             :class:`~transformers.AdamW` on your model and a scheduler given by
-            :func:`~transformers.get_linear_schedule_with_warmup` controlled by :obj:`args`. kwargs: Deprecated keyword
-            arguments.
+            :func:`~transformers.get_linear_schedule_with_warmup` controlled by :obj:`args`.
+        kwargs:
+            Deprecated keyword arguments.
     """
 
     def __init__(