I think JSON5 is fairly close to this: https://json5.org

I reckon the only thing it's missing to be truly accessible to non-techies is that string values still need to be quoted, i.e. you can't have:

key: this is my value

(I'm definitely not saying it would be a good idea to allow quotes to be dropped, just that that's the only potential stumbling block I see for non-techies.)

Edit to add: oh, hmm, I guess trailing commas are fiddly too. Possibly I want some even laxer variant of JSON that lets you use just newlines! :P