chore: spacing in peek method for Stack.java

Author: AmiyahJo

lesson_12/structs_java/structs_app/src/main/java/com/codedifferently/lesson12/Stack.java

@@ -25,8 +25,7 @@ public int pop() {
   public int peek() {
     if(top == null){
       //do stuff
-    }
-    
+    } 
     return 1;
   }