Support for JSON.rawJSON

[chrisdickinson]

Hi! Thanks for the great project! I'm opening an issue because I ran into a situation where I need to JSON.stringify an object containing a bigint. I can bail out back to parsing to/from strings, but it looks like one (forward-looking) way to accomplish this is via JSON.rawJSON, by doing something like:

JSON.stringify(
  {"bigint": 9223372036854775807n},
  (key, value) => typeof value === 'bigint' ? JSON.rawJSON(value.toString()) : value
)

It might be a bit soon to implement but I wanted to get the proposal on your radar!