Added bmp param in Cursor class docstring

Author: tekktrik

adafruit_cursorcontrol/cursorcontrol.py

@@ -31,6 +31,7 @@ class Cursor:
 
     :param ~displayio.Display display: CircuitPython display object.
     :param ~displayio.Group display_group: CircuitPython group object to append the cursor to.
+    :param ~displayio.Bitmap bmp: CircuitPython bitmap object to use as the cursor
     :param bool is_hidden: Cursor is hidden on init.
     :param int cursor_speed: Speed of the cursor, in pixels.
     :param int scale: Scale amount for the cursor in both directions.