[gtk+] Improve GtkAssistant docs

[Matthias Clasen <matthiasc src gnome org>]

commit c5e9526faf218a0ed1873d7e337052295b155e26
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Oct 30 21:25:21 2010 -0400

    Improve GtkAssistant docs

 gtk/gtkassistant.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkassistant.c b/gtk/gtkassistant.c
index 3fc0616..10241a3 100644
--- a/gtk/gtkassistant.c
+++ b/gtk/gtkassistant.c
@@ -32,6 +32,13 @@
  * operation splitted in several steps, guiding the user through its pages
  * and controlling the page flow to collect the necessary data.
  *
+ * The design of GtkAssistant is that it controls what buttons to show and
+ * to make sensitive, based on what it knows about the page sequence and
+ * the <link linkend="GtkAssistantPageType">type</link> of each page, in
+ * addition to state information like the page
+ * <link linkend="gtk-assistant-set-page-complete">completion</link> and
+ * <link linkend="gtk-assistant-commit">committed</link> status.
+ *
  * <refsect2 id="GtkAssistant-BUILDER-UI">
  * <title>GtkAssistant as GtkBuildable</title>
  * <para>