[glibmm] Gio::DBus::Proxy: Add some refreturn

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 3a979255a4e8441b4498d229201e235b692d13d6
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Fri Jul 29 17:06:27 2022 +0200

    Gio::DBus::Proxy: Add some refreturn
    
    get_connection() and get_interface_info() must add a reference.
    The error in get_connection() was noticed by 우정모 (kr.woaini).
    Fixes #102

 gio/src/dbusproxy.hg | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gio/src/dbusproxy.hg b/gio/src/dbusproxy.hg
index c3dfebbc..f8b47b1e 100644
--- a/gio/src/dbusproxy.hg
+++ b/gio/src/dbusproxy.hg
@@ -226,8 +226,8 @@ public:
 
   _WRAP_METHOD(ProxyFlags get_flags() const, g_dbus_proxy_get_flags)
 
-  _WRAP_METHOD(Glib::RefPtr<Connection> get_connection(), g_dbus_proxy_get_connection)
-  _WRAP_METHOD(Glib::RefPtr<const Connection> get_connection() const, g_dbus_proxy_get_connection)
+  _WRAP_METHOD(Glib::RefPtr<Connection> get_connection(), g_dbus_proxy_get_connection, refreturn)
+  _WRAP_METHOD(Glib::RefPtr<const Connection> get_connection() const, g_dbus_proxy_get_connection, 
refreturn, constversion)
 
   _WRAP_METHOD(Glib::ustring get_name() const, g_dbus_proxy_get_name)
   _WRAP_METHOD(Glib::ustring get_name_owner() const, g_dbus_proxy_get_name_owner)
@@ -259,8 +259,8 @@ public:
   _WRAP_METHOD(std::vector<Glib::ustring> get_cached_property_names() const, 
g_dbus_proxy_get_cached_property_names)
 
   _WRAP_METHOD(void set_interface_info(const Glib::RefPtr<InterfaceInfo>& info), 
g_dbus_proxy_set_interface_info)
-  _WRAP_METHOD(Glib::RefPtr<InterfaceInfo> get_interface_info(), g_dbus_proxy_get_interface_info)
-  _WRAP_METHOD(Glib::RefPtr<const InterfaceInfo> get_interface_info() const, 
g_dbus_proxy_get_interface_info, constversion)
+  _WRAP_METHOD(Glib::RefPtr<InterfaceInfo> get_interface_info(), g_dbus_proxy_get_interface_info, refreturn)
+  _WRAP_METHOD(Glib::RefPtr<const InterfaceInfo> get_interface_info() const, 
g_dbus_proxy_get_interface_info, refreturn, constversion)
 
   _WRAP_METHOD(
     void call(