[gtk/matthiasc/for-master] infobar: Update buildable docs

[Matthias Clasen <matthiasc src gnome org>]

commit 1599b659cff53b3e69a265ca33ad79a23171433a
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Aug 18 17:42:54 2021 -0400

    infobar: Update buildable docs
    
    Document the current state of GtkBuilder support in
    GtkInfoBar, not what we had in GTK3.
    
    Fixes: #4164

 gtk/gtkinfobar.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkinfobar.c b/gtk/gtkinfobar.c
index 2823f8afc1..452c64fbc4 100644
--- a/gtk/gtkinfobar.c
+++ b/gtk/gtkinfobar.c
@@ -106,15 +106,16 @@
  *
  * # GtkInfoBar as GtkBuildable
  *
- * The `GtkInfoBar` implementation of the `GtkBuildable` interface exposes
- * the content area and action area as internal children with the names
- * “content_area” and “action_area”.
- *
  * `GtkInfoBar` supports a custom <action-widgets> element, which can contain
  * multiple <action-widget> elements. The “response” attribute specifies a
  * numeric response, and the content of the element is the id of widget
  * (which should be a child of the dialogs @action_area).
  *
+ * `GtkInfoBar` supports adding action widgets by specifying “action” as
+ * the “type” attribute of a `<child>` element. The widget will be added
+ * either to the action area. The response id has to be associated
+ * with the action widget using the `<action-widgets>` element.
+ *
  * # CSS nodes
  *
  * `GtkInfoBar` has a single CSS node with name infobar. The node may get