Docs: tell people who _aren't_ using TypeScript that they may want a specific jsconfig.json

[benjie]

Essentially it needs the same as for TSconfig mentioned here: https://postgraphile.org/postgraphile/next/requirements#typescript-v500-optional

Otherwise you get red squigglies in VSCode under the import { ... } from "postgraphile/utils" or similar import paths.

{
  "compilerOptions": {
    "moduleResolution": "node16"
  }
}

[benjie]

cc @jemgillam