fix: renamed train files

src/main/java/oving7/train/CargoCar.java

@@ -7,7 +7,7 @@ package oving7.train;
  * @see TrainCar
  * @see PassengerCar
  */
-public class CargoCarDocs extends TrainCarDocs {
+public class CargoCar extends TrainCar {
 
     // TODO: Add fields here
 
@@ -20,7 +20,7 @@ public class CargoCarDocs extends TrainCarDocs {
      * 
      * @see CargoCarTest#testWeight()
      */
-    public CargoCarDocs(int deadWeight, int cargoWeight) {
+    public CargoCar(int deadWeight, int cargoWeight) {
         // TODO: Implement this constructor
         super(deadWeight);
     }

src/main/java/oving7/train/PassengerCar.java

@@ -7,7 +7,7 @@ package oving7.train;
  * @see TrainCar
  * @see CargoCar
  */
-public class PassengerCarDocs extends TrainCarDocs {
+public class PassengerCar extends TrainCar {
 
     // TODO: Add fields here
 
@@ -20,7 +20,7 @@ public class PassengerCarDocs extends TrainCarDocs {
      * 
      * @see PassengerCarTest#testWeight()
      */
-    public PassengerCarDocs(int deadWeight, int passengerCount) {
+    public PassengerCar(int deadWeight, int passengerCount) {
         // TODO: Implement this constructor
         super(deadWeight);
     }

src/main/java/oving7/train/Train.java

@@ -7,7 +7,7 @@ package oving7.train;
  * @see CargoCar
  * @see PassengerCar
  */
-public class TrainDocs {
+public class Train {
 
     // TODO: Add fields here
 

src/main/java/oving7/train/TrainCar.java

@@ -3,7 +3,7 @@ package oving7.train;
 /**
  * The class {@code TrainCar} represents a simple and general train car.
  */
-public class TrainCarDocs {
+public class TrainCar {
 
     // TODO: Add fields here
 
@@ -15,7 +15,7 @@ public class TrainCarDocs {
      * 
      * @see TrainCarTest#testDeadWeight()
      */
-    public TrainCarDocs(int deadWeight) {
+    public TrainCar(int deadWeight) {
         // TODO: Implement this constructor
     }