Unregister sensor listener on destroy

Also, remove superfluous comments.

app/src/main/java/eu/wa5p/lightmeter/MainActivity.kt

@@ -51,8 +51,6 @@ class MainActivity : ComponentActivity(), SensorEventListener {
             }
         }
 
-        // Get an instance of the sensor service, and use that to get an instance of
-        // a particular sensor.
         sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager
         illuminanceSensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT)
     }
@@ -83,16 +81,19 @@ class MainActivity : ComponentActivity(), SensorEventListener {
     }
 
     override fun onResume() {
-        // Register a listener for the sensor.
         super.onResume()
         sensorManager.registerListener(this, illuminanceSensor, SensorManager.SENSOR_DELAY_NORMAL)
     }
 
     override fun onPause() {
-        // Be sure to unregister the sensor when the activity pauses.
         super.onPause()
         sensorManager.unregisterListener(this)
     }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        sensorManager.unregisterListener(this)
+    }
 }
 
 @Composable