[Dev UI] Convert multi-line strings to JSON-escaped quotes when pasting into input box

[mbleigh]

It would be really handy for the input editor if, when you paste a multiline string, it automatically converted it to a JSON string. So i paste:

hello world
i am not "valid JSON" per se

and it turns it into

"hello world\ni am not \"valid JSON\" per se"

I asked an AI to built a proof of concept: 🙂 https://codepen.io/mbleigh/pen/GRbmvrG