text: Title: Set FEED_EXPORT_ENCODING="utf-8" in the default template
  Body: The default value for FEED_EXPORT_ENCODING (`None`) means `ensure_ascii=True` for JSON exports, because that was the existing behavior before that option was added. A better default is `"utf-8"`, which creates JSON files with `ensure_ascii=False`, so we decided to add this setting to the default template like we currently do with some other settings.
  
  The setting doc should also get a note about this like in https://docs.scrapy.org/en/latest/topics/settings.html#twisted-reactor