minor code comment update

noticed display brightness code comment said brightness was 0-15.  unsure when/where that was valid.  pretty sure it's 0.0 to 1.0 across all segment types now.

Author: DJDevon3

examples/ht16k33_animation_demo.py

@@ -16,7 +16,7 @@
 i2c = board.I2C()  # uses board.SCL and board.SDA
 # i2c = board.STEMMA_I2C()  # For using the built-in STEMMA QT connector on a microcontroller
 display = Seg14x4(i2c, auto_write=False)
-#   Brightness of the display (0 to 15)
+#   Brightness of the display (0.0 to 1.0)
 display.brightness = 0.3
 
 ani = Animation(display)