[Feature request] /editor opens prompt in $EDITOR

/editor should open your default text editor and allow composing/editing current prompt. I saw this in a competing tool and feels like a no brainer. The current readline support is reasonably good in the CC text box but since it doesn't (maybe can't?) support all the expected keyboard shortcuts it can feel a bit limiting. Allows people to use their own editor would completely free up any pressure to make the input box perfect-for-all.