Fix duty_cycle range.

Author: kattni

CircuitPython_Essentials/CircuitPython_PWM_Piezo.py

@@ -11,7 +11,7 @@
 while True:
     for f in (262, 294, 330, 349, 392, 440, 494, 523):
         piezo.frequency = f
-        piezo.duty_cycle = 65536 // 2  # On 50%
+        piezo.duty_cycle = 65535 // 2  # On 50%
         time.sleep(0.25)  # On for 1/4 second
         piezo.duty_cycle = 0  # Off
         time.sleep(0.05)  # Pause between notes