docs/library/pyb.rst: Update pyb.usb_mode() to mention VCP+MSC+HID.
docs/library/pyb.rst: Update pyb.usb_mode() to mention VCP+MSC+HID.

MrSurly/micropython,bvernoux/micropython,MrSurly/micropython,henriknelson/micropython,pramasoul/micropython,pramasoul/micropython,kerneltask/micropython,pozetroninc/micropython,kerneltask/micropython,tobbad/micropython,selste/micropython,selste/micropython,tobbad/micropython,pozetroninc/micropython,trezor/micropython,pozetroninc/micropython,henriknelson/micropython,tobbad/micropython,adafruit/circuitpython,kerneltask/micropython,trezor/micropython,pozetroninc/micropython,adafruit/circuitpython,pramasoul/micropython,trezor/micropython,MrSurly/micropython,adafruit/circuitpython,adafruit/circuitpython,bvernoux/micropython,kerneltask/micropython,henriknelson/micropython,bvernoux/micropython,selste/micropython,tobbad/micropython,MrSurly/micropython,kerneltask/micropython,tobbad/micropython,selste/micropython,MrSurly/micropython,pramasoul/micropython,henriknelson/micropython,adafruit/circuitpython,pramasoul/micropython,trezor/micropython,selste/micropython,pozetroninc/micropython,henriknelson/micropython,adafruit/circuitpython,trezor/micropython,bvernoux/micropython,bvernoux/micropython