No, but it is planned to make that the default.

Click on your target class. Then click on the note icon. Argo will generate the link automatically. The notes will be implemented for many UML artifacts in the next release .9.6

You can also right click to add a note as well! Be aware that you can add an undefined number of notes to any one class!

Be aware that your note will not appear in the source code documentation tab. But it will appear in the diagram view of the navigation pane (the left pane tree view).

Please see to do list.

Click direct class properties pane and start typing.

In fact, it would be interesting to see if you can type 'stereotypes' write in the class attribute box for generating XML diagrams.