[libpanel] example: add test for frame switcher tooltip

[Christian Hergert <chergert src gnome org>]

commit d1c568ad01c2c2550ea0a0e7e683acf2568e5731
Author: Christian Hergert <chergert redhat com>
Date:   Mon Sep 26 21:41:26 2022 -0700

    example: add test for frame switcher tooltip

 example/example-window.ui | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/example/example-window.ui b/example/example-window.ui
index 6291b6f..cfa7dad 100644
--- a/example/example-window.ui
+++ b/example/example-window.ui
@@ -372,6 +372,7 @@
                     <child>
                       <object class="PanelWidget">
                         <property name="title">Color</property>
+                        <property name="tooltip">Color</property>
                         <property name="can-maximize">true</property>
                         <property name="icon-name">color-select-symbolic</property>
                         <child>