fix deprecation warnings (#7033)

* fix deprecation warnings

* remove tests/test_tokenization_common.py's test_padding_to_max_length

* revert test_padding_to_max_length

src/transformers/modeling_funnel.py

@@ -127,7 +127,7 @@ def load_tf_weights_in_funnel(model, config, tf_checkpoint_path):
         skipped = False
         for m_name in name[1:]:
             if not isinstance(pointer, FunnelPositionwiseFFN) and re.fullmatch(r"layer_\d+", m_name):
-                layer_index = int(re.search("layer_(\d+)", m_name).groups()[0])
+                layer_index = int(re.search(r"layer_(\d+)", m_name).groups()[0])
                 if layer_index < config.num_hidden_layers:
                     block_idx = 0
                     while layer_index >= config.block_sizes[block_idx]:

src/transformers/modeling_tf_utils.py

@@ -699,7 +699,7 @@ class TFConv1D(tf.keras.layers.Layer):
 
 
 class TFSharedEmbeddings(tf.keras.layers.Layer):
-    """
+    r"""
     Construct shared token embeddings.
 
     The weights of the embedding layer is usually shared with the weights of the linear decoder when doing