Updated doc

ampel-firmware/co2_sensor.cpp

@@ -304,7 +304,7 @@ namespace sensor {
     if (timestep >= 2 && timestep <= 1800) {
       Serial.print(F("Setting Measurement Interval to : "));
       Serial.print(timestep);
-      Serial.println(F("s."));
+      Serial.println(F("s (change will only be applied after next measurement)."));
       scd30.setMeasurementInterval(timestep);
       config::measurement_timestep = timestep;
       led_effects::showKITTWheel(color::green, 1);