Update examples.md (#2862)

以下是webman中的response助手函数
/**
 * Response
 * @param int $status
 * @param array $headers
 * @param string $body
 * @return Response
 */
function response(string $body = '', int $status = 200, array $headers = []): Response
{
    return new Response($status, $headers, $body);
}
其中$body类型约束为string，这样改后是不是更规范一些。

docs/src/6.x/official-account/examples.md

@@ -33,7 +33,7 @@ class OfficialAccount
         $server = $app->getServer();
         $response = $server->serve();
 
-        return response($response->getBody());
+        return response($response->getBody()->getContents(), $response->getStatusCode(), $response->getHeaders());
     }
 }
 ```
@@ -71,7 +71,7 @@ class OfficialAccountController
         }
 
         if (method_exists($app, 'setCache')) {
-            $app->setCache(ApplicationContext::getContainer()->get(CacheInterface::class)  //可选，根据实际需求替换缓存
+            $app->setCache(ApplicationContext::getContainer()->get(CacheInterface::class));  //可选，根据实际需求替换缓存
         }
 
         $server = $app->getServer();