[MISC] typo fix (#19672)

Signed-off-by: Andy Xie <andy.xning@gmail.com>

vllm/config.py

@@ -1794,7 +1794,7 @@ class ParallelConfig:
     """The full name of the worker class to use. If "auto", the worker class
     will be determined based on the platform."""
     sd_worker_cls: str = "auto"
-    """The full name of the worker class to use for speculative decofing.
+    """The full name of the worker class to use for speculative decoding.
     If "auto", the worker class will be determined based on the platform."""
     worker_extension_cls: str = ""
     """The full name of the worker extension class to use. The worker extension