[gnome-builder] libide: fix .gir warning

[Christian Hergert <chergert src gnome org>]

commit 6a144c4f3655ea0347b3472b7c75412e848928ef
Author: Christian Hergert <christian hergert me>
Date:   Sun Feb 21 21:10:47 2016 -0800

    libide: fix .gir warning

 libide/preferences/ide-preferences-page.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/libide/preferences/ide-preferences-page.c b/libide/preferences/ide-preferences-page.c
index 5bb499b..6c76012 100644
--- a/libide/preferences/ide-preferences-page.c
+++ b/libide/preferences/ide-preferences-page.c
@@ -147,6 +147,11 @@ ide_preferences_page_add_group (IdePreferencesPage  *self,
   gtk_container_add (GTK_CONTAINER (self->box), GTK_WIDGET (group));
 }
 
+/**
+ * ide_preferences_page_get_group:
+ *
+ * Returns: (transfer none) (nullable): An #IdePreferencesGroup or %NULL.
+ */
 IdePreferencesGroup *
 ide_preferences_page_get_group (IdePreferencesPage *self,
                                 const gchar        *name)