Add shutDown method to HiscorePlugin

Remove navigation button from panel on shutdown

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

runelite-client/src/main/java/net/runelite/client/plugins/hiscore/HiscorePlugin.java

@@ -71,6 +71,12 @@ public class HiscorePlugin extends Plugin
 		menuManager.addPlayerMenuItem(LOOKUP);
 	}
 
+	@Override
+	protected void shutDown() throws Exception
+	{
+		ui.getPluginToolbar().removeNavigation(navButton);
+	}
+
 	@Subscribe
 	public void onLookupMenuClicked(PlayerMenuOptionClicked event)
 	{