doc: add openapi response content type to examples/ring-spec-swagger

examples/ring-spec-swagger/src/example/server.clj

@@ -67,6 +67,8 @@
         ["/download"
          {:get {:summary "downloads a file"
                 :swagger {:produces ["image/png"]}
+                :responses {200 {:description "an image"
+                                 :content {"image/png" {:schema string?}}}}
                 :handler (fn [_]
                            {:status 200
                             :headers {"Content-Type" "image/png"}