Document how to pretty print json?

[pmorch]

Is your feature request related to a problem? Please describe.
There are cases where it makes sense to want to indent JSON.

Describe the solution you'd like
I'd like to request that this be documented.

Example using the type and instance from README.md's Usage example

standard = json_codec.encode(portfolio, Portfolio)
print(f"standard:\n{standard}")

pretty = json_codec.encode(
    portfolio,
    Portfolio,
    post_encoder_func=lambda o: json.dumps(o, sort_keys=True, indent=4)
)
print(f'pretty:\n{pretty}')

Outputs:

standard:
{"currencies": [{"currency": "USD", "balance": 238.67}, {"currency": "EUR", "balance": 361.84}], "stocks": [{"ticker": "AAPL", "name": "Apple", "balance": 10}, {"ticker": "AMZN", "name": "Amazon", "balance": 10}]}

pretty:
{
    "currencies": [
        {
            "balance": 238.67,
            "currency": "USD"
        },
        {
            "balance": 361.84,
            "currency": "EUR"
        }
    ],
    "stocks": [
        {
            "balance": 10,
            "name": "Apple",
            "ticker": "AAPL"
        },
        {
            "balance": 10,
            "name": "Amazon",
            "ticker": "AMZN"
        }
    ]
}

And perhaps just having this issue is documentation enough. It would have allowed me to find it I think. I'll let you decide. Just closing it would be fine with me.