[Feature]: A way to normalize parsed values

[aradalvand]

Describe the feature

Consider this value object, whose string representation is customized to include a prefix (e.g. E1, E12, etc.).

[ValueObject<int>]
public readonly partial struct AggregateEdition : IEdition<AggregateEdition>, IValueObject<AggregateEdition, int>
{
	// NOTE: This is how to customize a Vogen value object's string representation — see https://github.com/SteveDunn/Vogen/pull/791/changes#diff-478e2c1cf89c8927b9cc135dffa8eceefb9473e374b46323fa2834a194eb3760R79
	public override string ToString() =>
		$"E{Value}";

	bool ISpanFormattable.TryFormat(
		Span<char> destination,
		out int charsWritten,
		ReadOnlySpan<char> format,
		IFormatProvider? provider
	)
	{
		if (!IsInitialized())
		{
			charsWritten = default;
			return false;
		}
		return destination.TryWrite($"E{Value}", out charsWritten);
	}
}

When these string representations, however, are parsed using AggregateEdition.TryParse, the parsing fails because the Parse/TryParse methods that Vogen generates simply forward the call to the underlying type's Parse/TryParse method(s) — and of course, int.TryParse("E12", out ...) is false.

I propose a second normalization method next to NormalizeInput(TUnderlyingType input) (the name is open to bikeshedding):

[ValueObject<int>]
public readonly partial struct AggregateEdition : IEdition<AggregateEdition>, IValueObject<AggregateEdition, int>
{
	// ...
   	private static string NormalizeParsed(string inputToParse) =>
		inputToParse.TrimStart('E');
}

The Vogen-generated Parse/TryParse implementations then simply invoke this method and feed its return value to the underlying type's Parse/TryParse — e.g. int.TryParse(NormalizeParsed("E12"), out ...) is true.