feat: add mirror of blur radius to config screen

- The blur radius can normally be configured in Minecraft's Accessibility settings. However, this has caused confusion for some users, so it can now also be configured via the config screen.

common/src/main/java/eu/midnightdust/blur/config/BlurConfig.java

@@ -2,6 +2,7 @@ package eu.midnightdust.blur.config;
 
 import com.google.common.collect.Lists;
 import eu.midnightdust.lib.config.MidnightConfig;
+import net.minecraft.client.MinecraftClient;
 
 import java.util.List;
 import java.util.function.Function;
@@ -22,6 +23,8 @@ public class BlurConfig extends MidnightConfig {
     public static int fadeOutTimeMillis = 300;
     @Entry(category = ANIMATIONS)
     public static BlurConfig.Easing animationCurve = Easing.FLAT;
+    @Entry(category = STYLE, isSlider = true, min = 0, max = 20)
+    public static int radius = 5;
     @Entry(category = STYLE)
     public static boolean useGradient = true;
     @Entry(category = STYLE, isColor = true, width = 7, min = 7)
@@ -43,6 +46,11 @@ public class BlurConfig extends MidnightConfig {
     @Entry(category = SCREENS) // Screens where the vanilla blur effect should be force disabled
     public static List<String> forceDisabledScreens = Lists.newArrayList();
 
+    @Override
+    public void writeChanges(String modid) {
+        MinecraftClient.getInstance().options.getMenuBackgroundBlurriness().setValue(radius);
+    }
+
     public enum Easing {
         // Based on https://gist.github.com/dev-hydrogen/21a66f83f0386123e0c0acf107254843
         // Thank you very much!