Merge pull request #110 from tlyu/comet-doc

comet: add doc for `background_color`

Author: jposada202020

adafruit_led_animation/animation/comet.py

@@ -37,6 +37,8 @@ class Comet(Animation):
     :param pixel_object: The initialised LED object.
     :param float speed: Animation speed in seconds, e.g. ``0.1``.
     :param color: Animation color in ``(r, g, b)`` tuple, or ``0x000000`` hex format.
+    :param background_color: Background color in ``(r, g, b)`` tuple, or ``0x000000`` hex format.
+                             Defaults to BLACK.
     :param int tail_length: The length of the comet. Defaults to 25% of the length of the
                             ``pixel_object``. Automatically compensates for a minimum of 2 and a
                             maximum of the length of the ``pixel_object``.