code: add .editorconfig for consistent code style across editors

[flyingthingsintothings]

EditorConfig is a well-known convention to share style settings across different editors. Adding one will make it easier for new contributors or people who like to use a different editor to contribute.

Solved Problem

I've switched from using Visual Studio Code to Neovim because the language server works quite a lot better. Neovim has no way to tell how to indent lines or how to represent tabs. Having this file tells a lot of different editors some basic information like how many spaces a tab represents, whether to indent with spaces or tabs, what the maximum line length should be... It can also tell editors to use a certain encoding, add a newline at the end of files and some other QOL settings.

The developer documentation mentions that a lot of files do not yet follow the style guidelines. This file could help to organically convert more and more files to the correct format as quite a lot of editors are automatically set up correctly.

Solution

• Add a .editorconfig file with shared options for all C/C++ files.

Changelog Entry

For release notes:

Feature/Bugfix XYZ
New parameter: XYZ_Z
Documentation: Need to clarify page ... / done, read docs.px4.io/...

Alternatives

I think this is the most general approach. It's used by a ton of editors. Sadly Visual Studio Code requires an extension, which could be added to the list of recommended extensions.

Context

I find it weird that nobody has suggested this before. Maybe I'm overlooking something but I can't find a single mention of EditorConfig anywhere in the issues or PRs. Sorry if this has been proposed before.