Implement changes

src/main/java/core/basesyntax/Bulldozer.java

@@ -5,6 +5,7 @@ public class Bulldozer extends Machine {
     public void doWork() {
         System.out.println("Bulldozer started its work.");
     }
+
     public void stopWork() {
         System.out.println("Bulldozer has stopped working.");
     }

src/main/java/core/basesyntax/Excavator.java

@@ -5,6 +5,7 @@ public class Excavator extends Machine {
     public void doWork() {
         System.out.println("Excavator started its work.");
     }
+
     public void stopWork() {
         System.out.println("Excavator has stopped working.");
     }

src/main/java/core/basesyntax/Machine.java

@@ -2,5 +2,6 @@
 
 public abstract class Machine {
     public abstract void doWork();
+
     public abstract void stopWork();
 }

src/main/java/core/basesyntax/Truck.java

@@ -6,6 +6,7 @@ public class Truck extends Machine {
     public void doWork() {
         System.out.println("Truck started its work.");
     }
+
     public void stopWork() {
         System.out.println("Truck has stopped working.");
     }