gtkactiongroup: clarify set_translation_domain docs

NULL is an actual useful value for
gtk_action_group_set_translation_domain, but this information is buried
in g_dgettext() documentation.

Be extra redundant, to make it obvious that NULL is ok.

https://bugzilla.gnome.org/show_bug.cgi?id=669636

diff --git a/gtk/gtkactiongroup.c b/gtk/gtkactiongroup.c
index cb16e44f0ec3ec30e6ab26d53bea867144069aba..4c03b7515b8c435abf356477c6e5ab6ab3214e71 100644 (file)
--- a/gtk/gtkactiongroup.c
+++ b/gtk/gtkactiongroup.c
@@ -1406,7 +1406,8 @@ dgettext_swapped (const gchar *msgid,
 /**
  * gtk_action_group_set_translation_domain:
  * @action_group: a #GtkActionGroup
- * @domain: the translation domain to use for g_dgettext() calls
+ * @domain: (allow-none): the translation domain to use for g_dgettext()
+ * calls, or %NULL to use the domain set with textdomain()
  * 
  * Sets the translation domain and uses g_dgettext() for translating the 
  * @label and @tooltip of #GtkActionEntry<!-- -->s added by