Add ruler to show the line limit in VSCode

[madd-games]

Thanks to this change if you open the project in VSCode, you will see a vertical line that shows on the 80th character, allowing you to see the limit as described in CONTRUBITING.md.

[guillaumechereau]

Do we need a specific VSCode config file for that? There is already a .editorconfig file, couldn't it be used by VSCode directly?

[madd-games]

It looks like VSCode currently does not support setting the rulers based on .editorconfig, they have a feature request for this but it is not implemented yet:

microsoft/vscode#111251

That being said, I wasn't aware about .editrconfig and it looks like it's VSCode devs' responsibility to implement this rather than adding it to this project. Feel free to abandon this PR.

[guillaumechereau]

Yeah, I think for now it's easier if you just keep your own local vscode config file. I don't use VSCode so I am not really familiar with it, but is it common to commit the editor config in the project? I don't do it for my own vim config files usually.

[madd-games]

Not sure how common it is; I do it for my own projects for things that will make the editor easier to use for other people (.e.g VScode allows you to set extension recommendations in a workspace). I also saw that in GIMP, the VSCode config file is indeed committed, and they have a ruler set there. The main benefit of VSCode is that it's a kind of "generic IDE", including good build features, that isn't tied to any language.

Ultimately up to you if you want this included. Personally I actually would prefer if VSCode devs added support for the ruler based on .editorconfig.