Update joystick.nim

Author: ringabout

src/sdl2/joystick.nim

@@ -205,7 +205,7 @@ proc joystickGetAxis*(joystick: JoystickPtr, axis: cint): int16 {.
   ## The axis indices start at index `0`.
 
 proc getAxis*(joystick: JoystickPtr, axis: cint): int16 {.inline.} =
-  ## Get the current state of an aSDL_xis control on a joystick.
+  ## Get the current state of an axis control on a joystick.
   ##
   ## The state is a value ranging from `-32768` to `32767`.
   ##