Enable multiple members to be defined at once

[SteveDunn]

Describe the feature

Something like:

[Intellenum]
[Members("Standard, Gold, Diamond, Platinum")
public partial class CustomerType
{
}

For .NET 7, we could inspect the underlying type for 'IAddition' (or whatever it's called in Generic Math) to be able to let the user specify the starting and incremental values

[SteveDunn]

Duplicate of #136