Fix TF start docstrings (#18991)

* Update our TF 2.0 input format tip across all models

* make style

templates/adding_a_new_model/cookiecutter-template-{{cookiecutter.modelname}}/modeling_tf_{{cookiecutter.lowercase_modelname}}.py

@@ -834,23 +834,27 @@ class TF{{cookiecutter.camelcase_modelname}}PreTrainedModel(TFPreTrainedModel):
 
     <Tip>
 
-    TF 2.0 models accepts two formats as inputs:
+    TensorFlow models and layers in `transformers` accept two formats as input:
 
     - having all inputs as keyword arguments (like PyTorch models), or
-    - having all inputs as a list, tuple or dict in the first positional arguments.
+    - having all inputs as a list, tuple or dict in the first positional argument.
 
-    This second option is useful when using [`tf.keras.Model.fit`] method which currently requires having
-    all the tensors in the first argument of the model call function: `model(inputs)`.
+    The reason the second format is supported is that Keras methods prefer this format when passing inputs to models
+    and layers. Because of this support, when using methods like `model.fit()` things should "just work" for you - just
+    pass your inputs and labels in any format that `model.fit()` supports! If, however, you want to use the second format outside of Keras methods like `fit()` and `predict()`, such as when creating
+    your own layers or models with the Keras `Functional` API, there are three possibilities you
+    can use to gather all the input Tensors in the first positional argument:
 
-    If you choose this second option, there are three possibilities you can use to gather all the input Tensors
-    in the first positional argument :
-
-    - a single Tensor with `input_ids` only and nothing else: `model(inputs_ids)`
+    - a single Tensor with `input_ids` only and nothing else: `model(input_ids)`
     - a list of varying length with one or several input Tensors IN THE ORDER given in the docstring:
     `model([input_ids, attention_mask])` or `model([input_ids, attention_mask, token_type_ids])`
     - a dictionary with one or several input Tensors associated to the input names given in the docstring:
     `model({"input_ids": input_ids, "token_type_ids": token_type_ids})`
 
+    Note that when creating models and layers with (subclassing)[https://keras.io/guides/making_new_layers_and_models_via_subclassing/]
+    then you don't need to worry about any of this, as you can just pass inputs like you would to any other Python
+    function!
+
     </Tip>
 
     Args:
@@ -2101,16 +2105,16 @@ class TF{{cookiecutter.camelcase_modelname}}PreTrainedModel(TFPreTrainedModel):
 
     <Tip>
 
-    TF 2.0 models accepts two formats as inputs:
+    TensorFlow models and layers in `transformers` accept two formats as input:
 
     - having all inputs as keyword arguments (like PyTorch models), or
-    - having all inputs as a list, tuple or dict in the first positional arguments.
+    - having all inputs as a list, tuple or dict in the first positional argument.
 
-    This second option is useful when using [`tf.keras.Model.fit`] method which currently requires having all
-    the tensors in the first argument of the model call function: `model(inputs)`.
-
-    If you choose this second option, there are three possibilities you can use to gather all the input Tensors in
-    the first positional argument :
+    The reason the second format is supported is that Keras methods prefer this format when passing inputs to models
+    and layers. Because of this support, when using methods like `model.fit()` things should "just work" for you - just
+    pass your inputs and labels in any format that `model.fit()` supports! If, however, you want to use the second format outside of Keras methods like `fit()` and `predict()`, such as when creating
+    your own layers or models with the Keras `Functional` API, there are three possibilities you
+    can use to gather all the input Tensors in the first positional argument:
 
     - a single Tensor with `input_ids` only and nothing else: `model(input_ids)`
     - a list of varying length with one or several input Tensors IN THE ORDER given in the docstring:
@@ -2118,6 +2122,10 @@ class TF{{cookiecutter.camelcase_modelname}}PreTrainedModel(TFPreTrainedModel):
     - a dictionary with one or several input Tensors associated to the input names given in the docstring:
     `model({"input_ids": input_ids, "token_type_ids": token_type_ids})`
 
+    Note that when creating models and layers with (subclassing)[https://keras.io/guides/making_new_layers_and_models_via_subclassing/]
+    then you don't need to worry about any of this, as you can just pass inputs like you would to any other Python
+    function!
+
     </Tip>
 
     Args: