[gtk+/gtk-3-22] Window: Mention GtkHeaderBar in set_titlebar() doc

[Daniel Boles <dboles src gnome org>]

commit fe220402cbc55533d4c95a7d713319c7daac59bd
Author: Daniel Boles <dboles src gnome org>
Date:   Fri Jan 12 21:26:36 2018 +0000

    Window: Mention GtkHeaderBar in set_titlebar() doc
    
    This is the typical thing passed here and what most users want, so we
    should mention it here, rather than requiring users to figure it out.

 gtk/gtkwindow.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index d4bc48c..c6aa542 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -4173,6 +4173,9 @@ on_titlebar_title_notify (GtkHeaderBar *titlebar,
  *
  * Sets a custom titlebar for @window.
  *
+ * A typical widget used here is #GtkHeaderBar, as it provides various features
+ * expected of a titlebar while allowing the addition of child widgets to it.
+ *
  * If you set a custom titlebar, GTK+ will do its best to convince
  * the window manager not to put its own titlebar on the window.
  * Depending on the system, this function may not work for a window