Update Unity for Visual Studio Code support

[petchema]

Just followed instructions given by the "Unity for Visual Studio Code" extension for Unity 2019 and Unity 2020:

• Remove the deprecated Visual Studio Code Editor package
• Update the Visual Studio Editor package to at least 2.0.20 (updated to current: 2.0.22) (- set Visual Studio Code as Unity's External C# editor - was already the case)
• Regenerate project files

I kept the comments added manually in .vscode/settings.json

I think it should have no impact on the game, it's purely for developers' convenience

[KABoissonneault]

Might be good to update the Rider package too, as some of us have moved to that.