Add note on making mode persistent

Author: sebromero

examples/indoor_air_quality.py

@@ -38,6 +38,7 @@ def display_sensor_data(sensor):
 
     # Set indoor air quality sensor mode to sulfur odor (default is indoor air quality)    
     # After switching modes you may need to wait some time before the sensor delivers the first data.
+    # Use set_mode(IndoorAirQualitySensorMode.SULFUR, persist=True) to make the change persistent.
     # indoor_air_quality_sensor.mode = IndoorAirQualitySensorMode.SULFUR
     # display_sensor_data(indoor_air_quality_sensor)
 

src/arduino_nicla_sense_env/outdoor_air_quality_sensor.py

@@ -198,6 +198,7 @@ def enabled(self, is_enabled: bool):
     def set_enabled(self, is_enabled: bool, persist = False) -> bool:
         """
         Enables or disables the outdoor air quality sensor and persists the setting to flash memory.
+        When the sensor is enabled after being disabled, the sensor will go back to the default mode.
 
         Parameters
         ----