Please use pan-down-symbolic icon instead of go-down-symbolic
While all GNOME apps are using pan-down-symbolic for telling the user there is a popover on a widget, Evince is using go-down-symbolic.
With Adwaita icons it's not an issue because they look similar, but with other icon themes the issue is very visible. Here a screenshot with Evince, Builder, Gedit and Nautilus, using Obsidian icons, where the issue is very obvious