Update error message and add pydoc for exception handling on subscribe

Author: allenporter

roborock/devices/device_manager.py

@@ -118,8 +118,7 @@ def device_creator(device: HomeDataDevice, product: HomeDataProduct) -> Roborock
         if device.pv != DeviceVersion.V1.value:
             raise NotImplementedError(
                 f"Device {device.name} has version {device.pv}, but only V1 devices "
-                f"are supported through the unified interface. Use the legacy "
-                f"RoborockMqttClientV1 or RoborockLocalClientV1 for this device."
+                f"are supported through the unified interface."
             )
         # Create V1 channel that handles both MQTT and local connections
         v1_channel = create_v1_channel(user_data, mqtt_params, mqtt_session, device)

roborock/devices/v1_channel.py

@@ -80,7 +80,9 @@ async def subscribe(self, callback: Callable[[RoborockMessage], None]) -> Callab
         """Subscribe to all messages from the device.
 
         This will establish MQTT connection first, and also attempt to set up
-        local connection if possible.
+        local connection if possible. Any failures to subscribe to MQTT will raise
+        a RoborockException. A local connection failure will not raise an exception,
+        since the local connection is optional.
         """
 
         if self._mqtt_unsub: