Fix sticker_type param serialization

src/payloads/codegen.rs

@@ -222,7 +222,9 @@ fn params(params: impl Iterator<Item = impl Borrow<Param>>) -> String {
             let field = &param.name;
             let ty = &param.ty;
             let flatten = match ty {
-                Type::RawTy(s) if s == "InputSticker" || s == "TargetMessage" => {
+                Type::RawTy(s)
+                    if s == "InputSticker" || s == "TargetMessage" || s == "StickerType" =>
+                {
                     "\n            #[serde(flatten)]"
                 }
                 _ => "",

src/payloads/create_new_sticker_set.rs

@@ -26,6 +26,7 @@ impl_payload! {
         }
         optional {
             /// Type of stickers in the set, pass “regular” or “mask”. Custom emoji sticker sets can't be created via the Bot API at the moment. By default, a regular sticker set is created.
+            #[serde(flatten)]
             pub sticker_type: StickerType,
             /// A JSON-serialized object for position where the mask should be placed on faces
             pub mask_position: MaskPosition,