Revert "improve documentation of training_args.py (huggingface#8270)"

This reverts commit 2352a4b.

src/transformers/training_args.py

@@ -48,19 +48,12 @@ class TrainingArguments:
             If :obj:`True`, overwrite the content of the output directory. Use this to continue training if
             :obj:`output_dir` points to a checkpoint directory.
         do_train (:obj:`bool`, `optional`, defaults to :obj:`False`):
-            Whether to run training or not. This argument is not directly used by :class:`~transformers.Trainer`, it's
-            intended to be used by your training/evaluation scripts instead. See the `example scripts
-            <https://github.com/huggingface/transformers/tree/master/examples>`__ for more details.
+            Whether to run training or not.
         do_eval (:obj:`bool`, `optional`):
-            Whether to run evaluation on the dev set or not. Will be set to :obj:`True` if :obj:`evaluation_strategy`
-            is different from :obj:`"no"`. This argument is not directly used by :class:`~transformers.Trainer`, it's
-            intended to be used by your training/evaluation scripts instead. See the `example scripts
-            <https://github.com/huggingface/transformers/tree/master/examples>`__ for more details.
+            Whether to run evaluation on the dev set or not. Will default to :obj:`evaluation_strategy` different from
+            :obj:`"no"`.
         do_predict (:obj:`bool`, `optional`, defaults to :obj:`False`):
-            Whether to run predictions on the test set or not. This argument is not directly used by
-            :class:`~transformers.Trainer`, it's intended to be used by your training/evaluation scripts instead. See
-            the `example scripts <https://github.com/huggingface/transformers/tree/master/examples>`__ for more
-            details.
+            Whether to run predictions on the test set or not.
         evaluation_strategy (:obj:`str` or :class:`~transformers.trainer_utils.EvaluationStrategy`, `optional`, defaults to :obj:`"no"`):
             The evaluation strategy to adopt during training. Possible values are: