Update modeling_utils.py (#28127)

In docstring for PreTrainedModel.resize_token_embeddings, correct definition of new_num_tokens parameter to read "the new number of tokens" (meaning the new size of the vocab) rather than "the number of new tokens" (number of newly added tokens only).

src/transformers/modeling_utils.py

@@ -1706,7 +1706,7 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin, GenerationMixin, PushToHubMix
 
         Arguments:
             new_num_tokens (`int`, *optional*):
-                The number of new tokens in the embedding matrix. Increasing the size will add newly initialized
+                The new number of tokens in the embedding matrix. Increasing the size will add newly initialized
                 vectors at the end. Reducing the size will remove vectors from the end. If not provided or `None`, just
                 returns a pointer to the input tokens `torch.nn.Embedding` module of the model without doing anything.
             pad_to_multiple_of (`int`, *optional*):