Readme - how to reuse more complex argument builders

[chris-rutkowski]

Hello, I really appreciate your library, it's great.

I miss in your documentation one thing - how to reuse more complex arguments in order not to reuse code.
Perhaps this may be because of call builder chain and complex genericness. C# is not my strength, but I'm getting there.

My builder:

var builder = FluentArgsBuilder.New()
    .Parameter<string>("-wallet").IsOptional()
    .PositionalArgument<BuySell>()
        .WithParser((v) => Enum.Parse<BuySell>(v, true))
        .IsRequired()
    .Call(direction => amount =>
    {
        ...
    }).Build();

As you see the BuySell enum builder is a "little" complex. Some other arguments will get even more complex.

Would you share your knowledge: how to refactor this code to be as follows:

var builder = FluentArgsBuilder.New()
    .Parameter<string>("-wallet").IsOptional()
    .BuySellPositionalArgument()
    .Call(direction => amount =>
    {
        ...
    }).Build();

Bonus point - the same for non-positional argument.s