[gtk/docs-gtk-org] gtk3: Link the treeview tutorial to the original website

[Emmanuele Bassi <ebassi src gnome org>]

commit 503853f9821b4f44e21d758a7a57af83f45bb4a2
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Aug 9 22:05:48 2021 +0100

    gtk3: Link the treeview tutorial to the original website

 gtk3/gtk/treeview-tutorial.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/gtk3/gtk/treeview-tutorial.md b/gtk3/gtk/treeview-tutorial.md
index f6df4edd5e..e57ce40807 100644
--- a/gtk3/gtk/treeview-tutorial.md
+++ b/gtk3/gtk/treeview-tutorial.md
@@ -4,7 +4,8 @@ Title: Tree View Tutorial
 
 This is a tutorial on how to use the GTK `GtkTreeView` widget through its C interface.
 
-This tutorial is based on the GTK 2.0 Tree View Tutorial by Tim-Philipp Müller.
+This tutorial is based on the [GTK 2.0 Tree View
+Tutorial](http://scentric.net/tutorial) by Tim-Philipp Müller.
 
 ## Lists and Trees: the `GtkTreeView` Widget