feat: add shared API operation metadata macro

crates/api-macros/tests/ui/multiple_bodies.rs

@@ -0,0 +1,17 @@
+use api_macros::api;
+
+pub struct FirstBody;
+pub struct SecondBody;
+pub struct Response;
+
+#[api]
+pub trait MultipleBodies {
+    #[post("/widgets")]
+    async fn create(
+        &self,
+        #[body] first: FirstBody,
+        #[body] second: SecondBody,
+    ) -> Response;
+}
+
+fn main() {}