docs: fix documentation error

fix documentation error

Signed-off-by: Tiago Barbosa <tbarbos@hotmail.com>

docs/getting-started/backstage.md

@@ -141,7 +141,7 @@ async function main() {
  // ...
  const pagerdutyEnv = useHotMemoize(module, () => createEnv('pagerduty'));
  // ...
- apiRouter.use('/pagerduty', await todo(pagerdutyEnv));
+ apiRouter.use('/pagerduty', await pagerduty(pagerdutyEnv));
 ```
 
 ### Configure Backend plugin API credentials