documentation for llama2 models (#25102)

* fix documentation

* changes

src/transformers/models/llama/convert_llama_weights_to_hf.py

@@ -282,6 +282,7 @@ def main():
     parser.add_argument(
         "--model_size",
         choices=["7B", "7Bf", "13B", "13Bf", "30B", "65B", "70B", "70Bf", "tokenizer_only"],
+        help="'f' models correspond to the finetuned versions, and are specific to the Llama2 official release. For more details on Llama2, checkout the original repo: https://huggingface.co/meta-llama",
     )
     parser.add_argument(
         "--output_dir",