add a marker for when channels/spaces with unread messages are scrolled off the screen #323
Description
Describe the problem
can be hard to find a space/channel with unread messages when it's scrolled off screen
Describe the solution you'd like
add some sort of indicator to the top/bottom of the left sidebar (for spaces with unread messages) or channel list (for channels with unread messages) that shows if any of the spaces/channels off screen in that scroll direction have unread messages
Alternatives considered
No response
Additional context
No response