get_visited
Description:
Retrieves the “visited” state of the `GtkLinkButton`.
The button becomes visited when it is clicked. If the URI is changed on the button, the “visited” state is unset again.
The state may also be changed using [method@Gtk.LinkButton.set_visited].
Parameters:
| this | 
           a `GtkLinkButton`  | 
      
Returns:
| 
           true if the link has been visited, false otherwise  |