qt network dialog: use icon for selected server, instead of "*"

Previously we added a " *" suffix to distinguish the selected/main server
in the list. However in case of an .onion address, anything we put as a
suffix inline is elided/truncated - as the address itself does not fit.
Hence we could instead use a prefix - and then why not use an icon.

electrum/gui/qt/network_dialog.py

@@ -157,11 +157,12 @@ class NodesListWidget(QTreeWidget):
             else:
                 x = connected_servers_item
             for i in interfaces:
-                star = ' *' if i == network.interface else ''
-                item = QTreeWidgetItem([f"{i.server.to_friendly_name()}" + star, '%d'%i.tip])
+                item = QTreeWidgetItem([f"{i.server.to_friendly_name()}", '%d'%i.tip])
                 item.setData(0, self.ITEMTYPE_ROLE, self.ItemType.CONNECTED_SERVER)
                 item.setData(0, self.SERVER_ADDR_ROLE, i.server)
                 item.setToolTip(0, str(i.server))
+                if i == network.interface:
+                    item.setIcon(0, read_QIcon("chevron-right.png"))
                 x.addChild(item)
             if n_chains > 1:
                 connected_servers_item.addChild(x)