style(kanata): use key symbols

[fnuttens]

Fancy symbols to help you memorize Arsenik’s layers 😎

I’m actually not so sure this is a good idea; sure, having clear symbols show up in Kanata’s logs can help newcomers, but I’d argue this is helpful for a limited time thanks to muscular memory.
Furthermore, these symbols are not so easy to handle with a text editor so I’m afraid it would do more harm to DX than good to beginners in the end.

Tell me what you think! 🙂