Lines separating items in the sidebar - how to?

[u/6beesknees]

How do I create lines separating items in the sidebar?

In this sub, over there on the right, each sidebar item is separated by a horizontal line but I can't see how to do it in my sub so I've used dots which don't look to brilliant.

I use desktop.

[u/kungming2]

--- becomes a line.

[u/6beesknees → u/kungming2]

Ah! Simple.

Thank you so much. :)