config: Change slider to white, so its easier to see. (#1262)

runelite-client/src/main/java/net/runelite/client/plugins/config/ConfigPanel.java

@@ -748,6 +748,7 @@ public class ConfigPanel extends PluginPanel
 						JSlider slider = new JSlider(min, max, value);
 						sliderValueLabel.setText(String.valueOf(slider.getValue()));
 						slider.setPreferredSize(new Dimension(80, 25));
+						slider.setBackground(Color.WHITE);
 						slider.addChangeListener((l) ->
 							{
 								sliderValueLabel.setText(String.valueOf(slider.getValue()));