This adds an [EditorConfig][homepage] file in the root of the repo. Most
editors support it [natively][native-support] or via a
[plugin][plugin-support].
This is particularly useful for occasional contributors, who with this
no longer need to configure the editor to properly show and format
source code.
[homepage]: https://editorconfig.org/
[native-support]: https://editorconfig.org/#pre-installed
[plugin-support]: https://editorconfig.org/#download
