NadekoBot.Extensions should now be fully annotated with nullable reference types as well as many classes from NadekoBot.Common

src/NadekoBot/Common/Yml/Rgba32Converter.cs

@@ -1,4 +1,5 @@
-using System.Globalization;
+#nullable disable
+using System.Globalization;
 using SixLabors.ImageSharp.PixelFormats;
 using YamlDotNet.Core;
 using YamlDotNet.Core.Events;
@@ -43,4 +44,4 @@ public class CultureInfoConverter : IYamlTypeConverter
         var ci = (CultureInfo)value;
         emitter.Emit(new Scalar(ci.Name));
     }
-}
+}