add library javafx-swt to classpath code example

Example: setting up javafx in eclipse vm argument

After you set your user library with the required JavaFX classes, click the
dropdown menu next to the run button
Click "Run Configurations" and go to the "Arguments" tab

In the "VM arguments" box copypaste the following:
--module-path="Add\path\to\JavaFX\lib" --add-modules=javafx.controls,javafx.fxml