Change detectors attributes based on DetectorType for MessageKit

dectectors.swift

extension MyAwesomeViewController: MessagesDisplayDelegate {
  
    // ...
    
    func detectorAttributes(for detector: DetectorType, and message: MessageType, at indexPath: IndexPath) -> [NSAttributedString.Key: Any] {
        switch detector {
        case .hashtag:
            return [.foregroundColor: UIColor.white]
        case .custom:
            return [.foregroundColor: UIColor.black]
        default: return MessageLabel.defaultAttributes
        }
    }
  
    // ...
    
}