Enable web extension for Vscode.dev

[bscan]

Currently if someone uses the vscode.dev version (or github version by pressing "." in a github repo), Raku code does not render well. The Navigator could be upgraded to a web extension which would provide syntax highlighting and snippets in the browser. The language server would not work due to the lack of Raku backend.

https://code.visualstudio.com/api/extension-guides/web-extensions