Not again...
This comes up very frequently.
Zeners can't protect MCU pins, because max pin voltage is not always 5volt.
Be skeptical about all advice given on internet pages that you can't correct or comment on without joining and logging in. Yes, that Designspark page has errors.
If you would need to protect that circuit from post#1, then use a Schottky diode from pin to VCC of the Arduino, instead of the useless zener.
The 10k resistor should go on the other side of the 200 ohm resistor (between pin and ground).
Not that it makes a lot of difference.
Leo..