tools/gen-cpydiff.py: Fix formatting of doc strings for new Black.
tools/gen-cpydiff.py: Fix formatting of doc strings for new Black.

Since version 21.4b0, Black now processes one-line docstrings by stripping
leading and trailing spaces, and adding a padding space when needed to
break up """"; see https://github.com/psf/black/pull/1740

This commit makes the Python code in this repository conform to this rule.

adafruit/circuitpython,bvernoux/micropython,henriknelson/micropython,adafruit/circuitpython,bvernoux/micropython,henriknelson/micropython,henriknelson/micropython,adafruit/circuitpython,henriknelson/micropython,bvernoux/micropython,bvernoux/micropython,bvernoux/micropython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,henriknelson/micropython