PLT Racket lets you use images and other rich objects in their editor, and provides a framework for rich editors which that editor is written in. So there are p

PLT Racket lets you use images and other rich objects in their editor, and provides a framework for rich editors which that editor is written in. So there are pieces there. Block oriented Forths used to use "shadow blocks" for documentation. You had a block that was code, and a fixed offset to a corresponding block that was documentation, with a keybinding to switch between them. Various tidbits of this have been done in Smalltalk (of course). But if you have already invested in a world of tool chains that assume ASCII or Unicode text streams as source code representation, then it's hard to get out of it.