Consider a true pretty-printed JSON format type

[scotttrinh]

We currently have three JSON output formats:

• json: which gives you proper JSON output
• json-lines: which gives https://jsonlines.org/ formatted lines, great for streaming
• json-pretty: which gives you json-lines except with colors and some CLI friendly formatting if you're in a terminal

What we don't have is an output format that will output an easy-to-read, formatted JSON file similar to what you'd get from JSON.stringify(result, null, INDENT_SIZE); or running the json output through something like Prettier, that is actually valid JSON. Mostly, I think this is what people would expect from the term json-pretty.