Missing public initializer for `Message.Title`

[martinprot]

The public struct MessageTitle (renamed Message.Title on master) does not expose its init method publicly, preventing the developer to create new Atem Messages.

For example, here's the implementation of a VideoOutput command, driving the Atems video output.

public struct VideoOutput: Serializable {
    public enum Output {
        case in1
        case in2
        case in3
        case in4
        case multiview
        case program
        case preview
    }
    let output: Output
    
    public static var title = MessageTitle(string: "CAuS")
        
    public init(with bytes: ArraySlice<UInt8>) throws {
        throw AtemMessageError.notImplemented
    }
    
    public init(output: Output) {
        self.output = output
    }

    public var dataBytes: [UInt8] {
        return switch output {
        case .in1: [1, 0, 0, 1]
        case .in2: [1, 0, 0, 2]
        case .in3: [1, 0, 0, 3]
        case .in4: [1, 0, 0, 4]
        case .multiview: [1, 0, 35, 41]
        case .program: [1, 0, 39, 26]
        case .preview: [1, 0, 39, 27]
        }
    }
    
    public var debugDescription: String {
        return "Video output set to \(output)"
    }
}

Without the public MessageTitle init, the compiler produces the following error:

'MessageTitle' initializer is inaccessible due to 'internal' protection level

Adding a public MessageTitle initializer would make this possible.