Add the ability to use the LED indicators for CAPS_LOCK et al.

[jfurcean]

This adds the ability to read the LED status of CAPS_LOCK, NUM_LOCK, SCROLL_LOCK, & COMPOSE.

LED_NUM_LOCK  # Works on Windows, RaspberryPi
LED_CAPS_LOCK # Works on Windows, RaspberryPi, Mac
LED_SCROLL_LOCK # Works on Windows
LED_COMPOSE  # Not Tested

Test Code

import usb_hid
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keycode import Keycode
import time

KEY_DELAY = .09

key_actions = [
    {
        "name": "Caps Lock",
        "keycode": Keycode.CAPS_LOCK,
        "led_code": Keyboard.LED_CAPS_LOCK
    },
    {
        "name": "Caps Lock",
        "keycode": Keycode.SCROLL_LOCK,
        "led_code": Keyboard.LED_SCROLL_LOCK
    },
    {
        "name": "Caps Lock",
        "keycode": Keycode.KEYPAD_NUMLOCK,
        "led_code": Keyboard.LED_NUM_LOCK
    },
]
kbd = Keyboard(usb_hid.devices)

for action in key_actions:
    for i in range(2):
        kbd.press(action['keycode'])
        time.sleep(KEY_DELAY)
        kbd.release(action['keycode'])
        print(f"{action['name']}: {kbd.led_on(action['led_code']}"))
    print()

[dhalbert]

Thanks for doing this! It is simple and small. A little more documentation is all that is needed.

[dhalbert]

Thank you for this valuable addition to the library!