Update docs/design_guide.rst
Update docs/design_guide.rst

Co-authored-by: Kattni <06f61fd7e70092c497363f5644c009038a5be747@adafruit.com>
adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython