Include IReadOnlyCollection and IReadOnlyDictionary

[sprengr]

This allows following conversions:

using System.Collections.Generic;

class Poco {
    public IReadOnlyCollection<int> Numbers { get; }
    public IReadOnlyDictionary<string, int> NumberPerKey { get; }
}

to

export interface Poco {
    Numbers: number[];
    NumbersPerKey: Record<string, number>;
}

[svenheden]

Thanks @sprengr!