This groups the pins for a port together and puts them in numerical order. It also adds ARDUINO pin names.
This enables MICROPY_HW_HAS_FLASH which got missed. The HW has UART2 on the 401 connected to the STLINK procesor which exposes it as USB serial. This connects that up so that you can get a REPL using the USB serial.
Includes full version of pins.csv file with correct mapping of the Nucleo STM32F401RE chip (LQFP64 package).