[gtk+] widget: Document child/sibling accessors

[Timm Bäder <baedert src gnome org>]

commit deb458c6568040f50916f1ac10e5dc93e0bcf0d5
Author: Timm Bäder <mail baedert org>
Date:   Sun Jan 8 16:58:27 2017 +0100

    widget: Document child/sibling accessors

 gtk/gtkwidget.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index d2001db..d80e25c 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -15708,6 +15708,14 @@ gtk_widget_render (GtkWidget            *widget,
   gsk_renderer_end_draw_frame (renderer, context);
 }
 
+/**
+ * gtk_widget_get_first_child:
+ * @widget: a #GtkWidget
+ *
+ * Returns: (transfer none) (nullable): The widget's first child
+ *
+ * Since: 3.90
+ */
 GtkWidget *
 gtk_widget_get_first_child (GtkWidget *widget)
 {
@@ -15716,6 +15724,14 @@ gtk_widget_get_first_child (GtkWidget *widget)
   return widget->priv->first_child;
 }
 
+/**
+ * gtk_widget_get_last_child:
+ * @widget: a #GtkWidget
+ *
+ * Returns: (transfer none) (nullable): The widget's last child
+ *
+ * Since: 3.90
+ */
 GtkWidget *
 gtk_widget_get_last_child (GtkWidget *widget)
 {
@@ -15724,6 +15740,14 @@ gtk_widget_get_last_child (GtkWidget *widget)
   return widget->priv->last_child;
 }
 
+/**
+ * gtk_widget_get_next_sibling:
+ * @widget: a #GtkWidget
+ *
+ * Returns: (transfer none) (nullable): The widget's next sibling
+ *
+ * Since: 3.90
+ */
 GtkWidget *
 gtk_widget_get_next_sibling (GtkWidget *widget)
 {
@@ -15732,6 +15756,14 @@ gtk_widget_get_next_sibling (GtkWidget *widget)
   return widget->priv->next_sibling;
 }
 
+/**
+ * gtk_widget_get_prev_sibling:
+ * @widget: a #GtkWidget
+ *
+ * Returns: (transfer none) (nullable): The widget's previous sibling
+ *
+ * Since: 3.90
+ */
 GtkWidget *
 gtk_widget_get_prev_sibling (GtkWidget *widget)
 {