Add pre-commit to project

[pocc]

pre-commit is a utility that runs before commits can be made. The use case here is to prettier to enforce markdown style. If there is interest, I'll make a PR with a .pre-commit-config.yaml, having run prettier over the README.md.

[caramelomartins]

@pocc Yeah, that's something that would be interesting.

[pocc]

Cool I've created a pre-commit config and run it against existing markdown files.

To run it, pre-commit install and a git pre-commit hook will be automatically created. It might be worth it to add this to the Contributing section.