examples: Fix channels.

This will be useful in desktop environments like GNOME.

* modules/rosenthal/examples/shepherd.desktop: New file.
* modules/rosenthal/services/desktop.scm (%rosenthal-skeletons)
[.config/autostart/shepherd.desktop]: Use it.

modules/rosenthal/examples/guix/channels.txt

@@ -0,0 +1,28 @@
+;;; -*- mode: scheme -*-
+
+;; info "(guix) Channels"
+;; https://guix.gnu.org/manual/devel/en/html_node/Channels.html
+
+(list (channel
+        (inherit %default-guix-channel)
+        (name 'guix)
+        (url "https://git.guix.gnu.org/guix.git"))
+
+      (channel
+        (name 'nonguix)
+        (url "https://gitlab.com/nonguix/nonguix")
+        (introduction
+         (make-channel-introduction
+          "897c1a470da759236cc11798f4e0a5f7d4d59fbc"
+          (openpgp-fingerprint
+           "2A39 3FFF 68F4 EF7A 3D29  12AF 6F51 20A0 22FB B2D5"))))
+
+      (channel
+        (name 'rosenthal)
+        (url "https://codeberg.org/hako/rosenthal.git")
+        (branch "trunk")
+        (introduction
+         (make-channel-introduction
+          "7677db76330121a901604dfbad19077893865f35"
+          (openpgp-fingerprint
+           "13E7 6CD6 E649 C28C 3385  4DF5 5E5A A665 6149 17F7")))))

modules/rosenthal/examples/shepherd.desktop

@@ -0,0 +1,5 @@
+# Start user Shepherd in environments that support XDG Autostart.
+[Desktop Entry]
+Type=Application
+Name=Shepherd
+Exec=shepherd

modules/rosenthal/services/desktop.scm

@@ -662,7 +662,10 @@ set-keymap us dvorak -o ctrl:nocaps\n")
      (license #f))))
 
 (define %rosenthal-skeletons
-  `((".config/emacs/init.el"
+  `((".config/autostart/shepherd.desktop"
+     ,(local-file "../examples/shepherd.desktop"))
+
+    (".config/emacs/init.el"
      ,(local-file "../examples/emacs/init.el"))
     (".config/emacs/init-fonts.el"
      ,(local-file "../examples/emacs/init-fonts.el"))