add override decorator.

Author: GdoongMathew

src/lightning/pytorch/accelerators/cuda.py

@@ -114,6 +114,7 @@ def register_accelerators(cls, accelerator_registry: _AcceleratorRegistry) -> No
         )
 
     @classmethod
+    @override
     def device_name(cls, device: Optional[_DEVICE] = None) -> str:
         if not cls.is_available():
             return "False"

src/lightning/pytorch/accelerators/xla.py

@@ -56,6 +56,7 @@ def register_accelerators(cls, accelerator_registry: _AcceleratorRegistry) -> No
         accelerator_registry.register("tpu", cls, description=cls.__name__)
 
     @classmethod
+    @override
     def device_name(cls, device: Optional[_DEVICE] = None) -> str:
         is_available = cls.is_available()
         if not is_available: