ReSharper: remove redundant code

Wox/Converters/StringNullOrEmptyToVisibilityConverter.cs

@@ -8,8 +8,6 @@ namespace Wox.Converters
 {
     public class StringNullOrEmptyToVisibilityConverter : ConvertorBase<StringNullOrEmptyToVisibilityConverter>
     {
-        public StringNullOrEmptyToVisibilityConverter() {  }
-
         public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
             return string.IsNullOrEmpty(value as string) ? Visibility.Collapsed : Visibility.Visible;