Add shutDown to DevtoolsPlugin

Remove navigation button on shutdown

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

runelite-client/src/main/java/net/runelite/client/plugins/devtools/DevToolsPlugin.java

@@ -62,6 +62,7 @@ public class DevToolsPlugin extends Plugin
 	int itemIndex = -1;
 
 	private Font font;
+	private NavigationButton navButton;
 
 	@Override
 	public void configure(Binder binder)
@@ -74,7 +75,7 @@ public class DevToolsPlugin extends Plugin
 	protected void startUp() throws Exception
 	{
 		final DevToolsPanel panel = injector.getInstance(DevToolsPanel.class);
-		final NavigationButton navButton = new NavigationButton(
+		navButton = new NavigationButton(
 			"Developer Tools",
 			ImageIO.read(getClass().getResourceAsStream("devtools_icon.png")),
 			() -> panel);
@@ -85,6 +86,12 @@ public class DevToolsPlugin extends Plugin
 			.deriveFont(Font.BOLD, 16);
 	}
 
+	@Override
+	protected void shutDown() throws Exception
+	{
+		ui.getPluginToolbar().removeNavigation(navButton);
+	}
+
 	@Override
 	public Overlay getOverlay()
 	{