[Feature Request] move rocket auto-generated code out of source files

[e111077]

It's really cool that nothing is hidden from you on how Rocket works and it's cool pair-programming with a robot, but the auto-generated code in the source is a bit of an issue for me:

1. It pollutes my cmd+z stack as I add WCs into the template
2. It makes me afraid of what I can and cannot touch
3. vscode auto-imports will fall inside that region

Maybe some indirection might be necessary here: perhaps make this all output in a build directory or maybe even create your own file format / file extension?