Add comments hotkey for the Playground

[pluralia]

The comments hotkey Cmd + / (Ctrl + / for Windows) is very common editors feature --- would be cool to have it for the Langium Playground.

[montymxb]

I think this is supported in Monaco + Langium as is? @kaisalmen do you know more about this? Or perhaps it's necessary to add additional handling 🤔 . I've also noticed that it doesn't work as expected in Monaco at times, but I swear it did back in Sept. when I was preparing things for MiniLogo in the web.

[kaisalmen]

There seem to be an issues. CTRL + K works in the monaco-editor built-in TypeScript editor, but there also CTRL + / does not work. Seems to be a more general issue. I have to investigate

[spoenemann]

It could be related to the general problems of handling keyboard layouts in the browser. We have made quite a lot of effort to get it right in Theia: eclipse-theia/theia#4724

[montymxb]

This works now, closing as resolved.