Add option to advertise dedicated servers to LAN.

src/main/java/net/minecraftforge/common/ForgeConfig.java

@@ -30,6 +30,8 @@ public class ForgeConfig {
 
         public final ConfigValue<String> permissionHandler;
 
+        public final BooleanValue advertiseDedicatedServerToLan;
+
         Server(ForgeConfigSpec.Builder builder) {
             builder.comment("Server configuration settings")
                    .push("server");
@@ -69,6 +71,11 @@ public class ForgeConfig {
                     .translation("forge.configgui.permissionHandler")
                     .define("permissionHandler", "forge:default_handler");
 
+            advertiseDedicatedServerToLan = builder
+                    .comment("Set this to true to enable advertising the dedicated server to local LAN clients so that it shows up in the Multiplayer screen automatically.")
+                    .translation("forge.configgui.advertiseDedicatedServerToLan")
+                    .define("advertiseDedicatedServerToLan", true);
+
             builder.pop();
         }
     }