[mutter] window: Fix introspection warnings

[Carlos Garnacho <carlosg src gnome org>]

commit 781ec74fd2bb505de7abde6e0641a62ab6ef728a
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Dec 14 15:55:36 2018 +0100

    window: Fix introspection warnings
    
    (transfer none) was added for fundamental types, which can't be
    transfered.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/356

 src/core/window.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/core/window.c b/src/core/window.c
index 66d34ba9f..60252c4c1 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -8524,7 +8524,7 @@ meta_window_is_stackable (MetaWindow *window)
  *
  * Returns the window id associated with window.
  *
- * Returns: (transfer none): The window id
+ * Returns: The window id
  */
 uint64_t
 meta_window_get_id (MetaWindow *window)
@@ -8538,7 +8538,7 @@ meta_window_get_id (MetaWindow *window)
  *
  * Returns the #MetaWindowClientType of the window.
  *
- * Returns: (transfer none): The root ancestor window
+ * Returns: The root ancestor window
  */
 MetaWindowClientType
 meta_window_get_client_type (MetaWindow *window)