docs: Update all WiPy docs to reflect the new API.

cc3200/mods/modmachine.c

cc3200/mods/pybuart.c

docs/conf.py

docs/library/index.rst

docs/library/machine.ADC.rst

docs/library/machine.HeartBeat.rst

docs/library/machine.I2C.rst

docs/library/machine.Pin.rst

docs/library/machine.RTC.rst

docs/library/machine.SD.rst

docs/library/machine.SPI.rst

docs/library/machine.Timer.rst

docs/library/machine.UART.rst

docs/library/machine.WDT.rst

docs/library/machine.rst

docs/library/network.rst

docs/library/os.rst

docs/library/pyb.ADC.rst

docs/library/pyb.I2C.rst

docs/library/pyb.Pin.rst