[libhandy] examples: Add a few mnemonics to the preferences window

[Adrien Plazas <aplazas src gnome org>]

commit 6effa6598cacc33b4e4768a045f3df0670e1b623
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Sat Oct 3 14:21:41 2020 +0500

    examples: Add a few mnemonics to the preferences window
    
    This will help with reproducing a bug with search.

 examples/hdy-demo-preferences-window.ui | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/examples/hdy-demo-preferences-window.ui b/examples/hdy-demo-preferences-window.ui
index f46bb6bb..a6a16f59 100644
--- a/examples/hdy-demo-preferences-window.ui
+++ b/examples/hdy-demo-preferences-window.ui
@@ -34,13 +34,15 @@
             <property name="visible">True</property>
             <child>
               <object class="HdyActionRow">
-                <property name="title" translatable="yes">Layout</property>
+                <property name="title" translatable="yes">L_ayout</property>
+                <property name="use_underline">True</property>
                 <property name="visible">True</property>
               </object>
             </child>
             <child>
               <object class="HdyActionRow">
-                <property name="title" translatable="yes">Search</property>
+                <property name="title" translatable="yes">S_earch</property>
+                <property name="use_underline">True</property>
                 <property name="visible">True</property>
               </object>
             </child>