I am trying to use the String.StringInterpolation extension with NumberFormatter() and .spellOut however this return the string as lowercase string (one, two etc) how would like to return string as uppercase for the the first letter then lowercase for the rest (One, Two etc) but only can add .uppercased() or .lowercased(). If anyone has any ideas?

Here some example code

struct ContentView: View {
    @State private var number = 1

    var body: some View {
        let numberString = "\(format: number, style: .spellOut)"

        return VStack {
            Text(numberString.uppercased())

            Stepper("Number", value: $number, in: 1...10)
            .padding()
        }

    }
}

extension String.StringInterpolation {
    mutating func appendInterpolation(format number: Int, style: NumberFormatter.Style) {
        let formatter = NumberFormatter()
        formatter.numberStyle = style

        if let result = formatter.string(from: number as NSNumber) {
            appendLiteral(result)
        }
    }
}

Appreciate yout help in advance

Cheers. Could not find it anywhere in String documents