add definition of libdbus-specific connection-disconnected signal

Author: Lawrence D'Oliveiro

dbussy.py

@@ -6273,6 +6273,20 @@ def to_string(obj, indent) :
                           ),
                     ],
               ),
+        DBUS.INTERFACE_LOCAL :
+            # note implementation of this is hard-coded inside, and specific to, libdbus
+            Introspection.Interface
+              (
+                name = DBUS.INTERFACE_LOCAL,
+                signals =
+                    [
+                        Introspection.Interface.Signal(name = "Disconnected"),
+                          # auto-generated by libdbus with path = DBUS.PATH_LOCAL
+                          # when connection is closed; cannot be explicitly sent by
+                          # clients. Documented here:
+                          # <https://lists.freedesktop.org/archives/dbus/2018-October/017587.html>
+                    ],
+              ),
         DBUS.INTERFACE_DBUS :
             Introspection.Interface
               (