chore: update comments to clarify close call

Author: allenporter

tests/devices/test_device_manager.py

@@ -148,6 +148,7 @@ async def mock_home_data_with_counter(*args, **kwargs) -> HomeData:
         await device_manager.close()
         assert len(devices2) == 1
 
+        # Ensure closing again works without error
         await device_manager.close()