[FR] Add code formatter

[p3l1]

Hello there,

many other language plugins are providing a code formatter to format the given code using the Format Document command within VSCode. For now I am using the method mentioned here to generate readable pkl files from json, but I would really like the option within VSCode.

Thanks for your work on Pkl so far!

[stackoverflow]

A formatter is definitely something we want in the language. It'll probably come either in the LSP or as a command in the CLI itself.

[Redauser]

Coding without a proper formatter is extremely frustrating, there is definitely the need to add this functionality!