Add information about the UNO R4 to the documentation for analogReadResolution()

[eMUQI]

According to the datasheet and documentation, the UNO R4 boards support up to 14-bit ADC. https://docs.arduino.cc/resources/datasheets/ABX00080-datasheet.pdf https://docs.arduino.cc/resources/datasheets/ABX00087-datasheet.pdf https://docs.arduino.cc/tutorials/uno-r4-minima/adc-resolution/ https://docs.arduino.cc/tutorials/uno-r4-wifi/adc-resolution/