That's CodeMirror and it doesn't do anything except alter content (depending on what parameters you have configured for it) and apply coloring. Its JS for rebinding is unreliable so it won't work well with multi-code output (when adding more than 1 code usage in a code action) and it slows the page down. It brings little value as an actual editor. I recommend using an external editor where you'll gain actual value then just copy the code over. There's several well made free ones like Visual Studio Code, Netbrains, etc..
There are no plans to implement support for an editor there, sorry.