inserting macros instead of hard coded board names

docs/lessons/love-meter/activity.md

@@ -28,7 +28,7 @@ input.onPinPressed(TouchPin.P0, () => {
 
 ```
 
-Finally, let's show that number on the micro:bit. You are registering an event handler that will execute on the BBC micro:bit whenever the user holds the GND pin with one hand, and presses pin 0 with the other hand, thus completing a circuit
+Finally, let's show that number on the micro:bit. You are registering an event handler that will execute on the @boardname@ whenever the user holds the GND pin with one hand, and presses pin 0 with the other hand, thus completing a circuit
 
 
 ```blocks