Add support for attachments (#2088)

* Enforce valid button styles

* support command option type 11

* missing '.'

* Added type converter.

Co-authored-by: Cat <lumitydev@gmail.com>
Co-authored-by: CottageDwellingCat <80918250+CottageDwellingCat@users.noreply.github.com>

Co-authored-by: FeroxFoxxo <feroxfoxxo@gmail.com>
Co-authored-by: Cat <lumitydev@gmail.com>
Co-authored-by: CottageDwellingCat <80918250+CottageDwellingCat@users.noreply.github.com>

src/Discord.Net.Interactions/InteractionService.cs

@@ -163,6 +163,7 @@ namespace Discord.Interactions
             {
                 [typeof(IChannel)] = typeof(DefaultChannelConverter<>),
                 [typeof(IRole)] = typeof(DefaultRoleConverter<>),
+                [typeof(IAttachment)] = typeof(DefaultAttachmentConverter<>),
                 [typeof(IUser)] = typeof(DefaultUserConverter<>),
                 [typeof(IMentionable)] = typeof(DefaultMentionableConverter<>),
                 [typeof(IConvertible)] = typeof(DefaultValueConverter<>),

src/Discord.Net.Interactions/TypeConverters/DefaultEntityTypeConverter.cs

@@ -20,6 +20,11 @@ namespace Discord.Interactions
         }
     }
 
+    internal class DefaultAttachmentConverter<T> : DefaultEntityTypeConverter<T> where T : class, IAttachment
+    {
+        public override ApplicationCommandOptionType GetDiscordType() => ApplicationCommandOptionType.Attachment;
+    }
+
     internal class DefaultRoleConverter<T> : DefaultEntityTypeConverter<T> where T : class, IRole
     {
         public override ApplicationCommandOptionType GetDiscordType ( ) => ApplicationCommandOptionType.Role;