micro:bit croc clip keeper

Works with a micro:bit v1 or v2. Note that the edge comes *very* close to some small components 10 mm from the edge of the board, but shouldn't touch or interfere unless your printer's Z-scale is incorrect. As ever, take care fitting anything to a circuit board …

tiny guard piece to stop croc clips / alligator clips shorting out on your [micro:bit](https://microbit.org/). Designed entirely from the [Kitronik mechanical drawings](https://kitronik.co.uk/blogs/resources/bbc-microbit-cad-resources), as the official ones are useless.