Add some useful comments

Signed-off-by: Stanislav Trailov <Stanislav.Trailov@bosch.io>

hawkbit-core/src/main/java/org/eclipse/hawkbit/repository/DistributionSetTagFields.java

@@ -38,7 +38,7 @@ public enum DistributionSetTagFields implements FieldNameProvider {
   COLOUR("colour"),
 
   /**
-   *
+   * Distribution set fields
    */
   DISTRIBUTIONSET("assignedToDistributionSet",
       DistributionSetFields.ID.getFieldName(), DistributionSetFields.NAME.getFieldName());

hawkbit-core/src/main/java/org/eclipse/hawkbit/repository/TargetTagFields.java

@@ -38,7 +38,7 @@ public enum TargetTagFields implements FieldNameProvider {
   COLOUR("colour"),
 
   /**
-   *
+   * Target fields
    */
   TARGET("assignedToTargets",
       TargetFields.ID.getFieldName(), TargetFields.NAME.getFieldName());