- fix: unset image/podcast if it's provided in content
  example: https://www.reddit.com/r/funny.rss
- fix: use only 1 item content field
- etc: test new parser extensively
- etc: readability strips out code comments in https://2ality.com/2021/01/looping-over-arrays.html
- fix: loading items (by scrolling down) is glitching while feeds are refreshing