fix: Fix checkstyle error

Author: iluwatar

singleton/src/main/java/com/iluwatar/singleton/ThreadSafeLazyLoadedIvoryTower.java

@@ -44,9 +44,9 @@ private ThreadSafeLazyLoadedIvoryTower() {
    * The instance doesn't get created until the method is called for the first time.
    */
   public static synchronized ThreadSafeLazyLoadedIvoryTower getInstance() {
-      if (instance == null) {
-          instance = new ThreadSafeLazyLoadedIvoryTower();
-      }
+    if (instance == null) {
+      instance = new ThreadSafeLazyLoadedIvoryTower();
+    }
     return instance;
   }
 }