Hi mid
Thank you so much, this small thing is a huge help for me..
BTW, since other people might not know it,
maybe the developers of itch.io can consider one of the following:
1) To make a setting in the Account settings, for choosing the default [Enter] behavior: either New Paragraph, or New Line.
if #1 is too complicated, then maybe instead:
2) Add a small note in the new Thread/Post page, on the side, mentioning the difference between [Enter] and Shift-[Enter]..
It will really help other people who don't know what causes this, like I was, till 10 minute ago after you helped me..