[tokenizer] fix type

with a ',', it becomes a tuple, and deemed as True.

vllm/engine/arg_utils.py

@@ -15,7 +15,7 @@ class EngineArgs:
     """Arguments for vLLM engine."""
     model: str
     tokenizer: Optional[str] = None
-    disable_tokenizer: bool = False,
+    disable_tokenizer: bool = False
     tokenizer_mode: str = 'auto'
     trust_remote_code: bool = False
     download_dir: Optional[str] = None