text: Title: Improve docs regarding error reporting under asgi; add FAQ item
  Body: Hello, I feel like i am missing something because falcon/uvicorn doesn't show any error traceback when there's a server error. Why is that? Just to note, i've used Flask for almost five years and am now migrating to falcon, so i have never used before uvicorn/falcon.
  
  ```python
  import falcon
  import falcon.asgi
  
  
  class ThingsResource:
      async def on_get(self, req, resp):
          raise ValueError('foo')
  
  
  app = falcon.asgi.App()
  
  things = ThingsResource()
  app.add_route('/things', things)
  ```
  
  ```
  uvicorn main:app --reload --log-level debug
  ```
  ```
  INFO:     Will watch for changes in these directories: ['falcon-server']
  INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
  INFO:     Started reloader process [6088] using StatReload
  INFO:     Started server process [15700]
  INFO:     Waiting for application startup.
  INFO:     Application startup complete.
  INFO:     127.0.0.1:59567 - "GET /things HTTP/1.1" 500 Internal Server Error # No traceback.
  ```