Change the behaviour of the Comment Poll

[viktorsmari]

Problem:
All comments are polled every 3 seconds from the /api/.
They are always re-rendered, no matter what.

• This is annoying if you are reading a comment that can be scrolled sideways.
• This is annoying if you are trying to select / highlight text, in order to copy it.

Screenshot:

Video:
https://imgur.com/a/5pAs3oK

How to reproduce:
Try reading the first comment and scroll it sideways. https://x.piratar.is/polity/1/issue/408/
Try highlighting any text in comment and wait 2-3 seconds.

Possible solutions:
Only re-render comments that have changed, or are new.