Update README.MD

README.MD

@@ -5,9 +5,9 @@ import Stepper
 from machine import Pin
 s1 = Stepper.create(Pin(16,Pin.OUT),Pin(17,Pin.OUT),Pin(5,Pin.OUT),Pin(18,Pin.OUT), delay=2)
 s1.step(100)
-s1.step(100,-1)
+s1.step(100,-1) # or s1.step(-100)
 s1.angle(180)
-s1.angle(360,-1)
+s1.angle(360,-1) # or s1.angle(-360)
 ```
 function `angle` is angle, and the PIN map:
 `IN1` link `PIN_16`