[glade-web] Update manual, API and tutorial links

[Alberto Fanjul <albfan src gnome org>]

commit 1f73e097425e56d5a5477d7f222a7f068a16dfd5
Author: Alberto Fanjul <albertofanjul gmail com>
Date:   Wed May 20 16:06:07 2020 +0200

    Update manual, API and tutorial links

 head.src | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/head.src b/head.src
index fa98a09..e8725c8 100644
--- a/head.src
+++ b/head.src
@@ -34,8 +34,9 @@
          </ul>
         <h1>Documentation</h1>
           <ul>
-            <li><a href="http://live.gnome.org/Glade/Tutorials";>Tutorials</a></li>
-            <li><a href="http://library.gnome.org/devel/gladeui/3.20/";>API Reference</a></li>
+            <li><a href="https://wiki.gnome.org/Apps/Glade/Tutorials";>Tutorials</a></li>
+            <li><a href="https://developer.gnome.org/gladeui/stable/";>API Reference</a></li>
+            <li><a href="https://help.gnome.org/users/glade/stable/";>User manual</a></li>
           </ul>
         <h1>Help</h1>
           <ul>