docs/glossary: Elaborate on possible MicroPython port differences.
docs/glossary: Elaborate on possible MicroPython port differences.

State that this doc describes generic, "core" MicroPython functionality,
any particular port may diverge in both directions, by both omitting
some functionality, and adding more, both cases described outside the
generic documentation.

ryannathans/micropython,SHA2017-badge/micropython-esp32,torwag/micropython,MrSurly/micropython,ryannathans/micropython,kerneltask/micropython,micropython/micropython-esp32,SHA2017-badge/micropython-esp32,AriZuu/micropython,henriknelson/micropython,AriZuu/micropython,tobbad/micropython,Timmenem/micropython,bvernoux/micropython,swegener/micropython,SHA2017-badge/micropython-esp32,tobbad/micropython,MrSurly/micropython-esp32,oopy/micropython,blazewicz/micropython,pfalcon/micropython,kerneltask/micropython,adafruit/circuitpython,adafruit/circuitpython,swegener/micropython,infinnovation/micropython,Timmenem/micropython,adafruit/micropython,tobbad/micropython,Timmenem/micropython,SHA2017-badge/micropython-esp32,pozetroninc/micropython,AriZuu/micropython,MrSurly/micropython-esp32,trezor/micropython,MrSurly/micropython,MrSurly/micropython-esp32,pfalcon/micropython,torwag/micropython,micropython/micropython-esp32,selste/micropython,micropython/micropython-esp32,ryannathans/micropython,bvernoux/micropython,MrSurly/micropython,oopy/micropython,AriZuu/micropython,pozetroninc/micropython,MrSurly/micropython-esp32,adafruit/circuitpython,infinnovation/micropython,tralamazza/micropython,blazewicz/micropython,kerneltask/micropython,pozetroninc/micropython,trezor/micropython,swegener/micropython,selste/micropython,oopy/micropython,trezor/micropython,tralamazza/micropython,adafruit/micropython,selste/micropython,pramasoul/micropython,tobbad/micropython,torwag/micropython,MrSurly/micropython-esp32,torwag/micropython,adafruit/circuitpython,lowRISC/micropython,infinnovation/micropython,lowRISC/micropython,lowRISC/micropython,ryannathans/micropython,adafruit/circuitpython,pramasoul/micropython,trezor/micropython,tralamazza/micropython,dmazzella/micropython,blazewicz/micropython,ryannathans/micropython,blazewicz/micropython,adafruit/micropython,SHA2017-badge/micropython-esp32,kerneltask/micropython,dmazzella/micropython,henriknelson/micropython,MrSurly/micropython,pramasoul/micropython,micropython/micropython-esp32,pozetroninc/micropython,trezor/micropython,pfalcon/micropython,selste/micropython,lowRISC/micropython,micropython/micropython-esp32,MrSurly/micropython,adafruit/micropython,dmazzella/micropython,oopy/micropython,swegener/micropython,tralamazza/micropython,adafruit/circuitpython,henriknelson/micropython,Timmenem/micropython,pramasoul/micropython,bvernoux/micropython,pramasoul/micropython,henriknelson/micropython,lowRISC/micropython,bvernoux/micropython,torwag/micropython,tobbad/micropython,blazewicz/micropython,pozetroninc/micropython,dmazzella/micropython,adafruit/micropython,henriknelson/micropython,infinnovation/micropython,pfalcon/micropython,infinnovation/micropython,Timmenem/micropython,selste/micropython,bvernoux/micropython,AriZuu/micropython,oopy/micropython,pfalcon/micropython,swegener/micropython,kerneltask/micropython