#178: add hint to rest api port

Author: Death111

src/main/resources/layouts/settings.fxml

@@ -391,6 +391,7 @@
                                              </font>
                                           </Label>
                                           <Label text="Changes will not take effect until the next start of KeepTime" />
+                                          <Label layoutX="11.0" layoutY="34.0" prefHeight="42.0" prefWidth="393.0" text="When the port is in use KeepTime will fail to start. Adapt the port in application.properties if this is the case." wrapText="true" />
                                        </children>
                                     </VBox>
                                  </children>