Fix typo and make ListBoxItems toggleable in Demo (#3680)

* fixed typo in tool tip in MenusAndToolBars

* Make ListBoxItem in Demo actually toggleable that should be toggleable

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Co-authored-by: Corvin Szimion <[email protected]>

Author: corvinsz

src/MainDemo.Wpf/MenusAndToolBars.xaml

@@ -216,8 +216,8 @@
 
           <Separator />
 
-          <ListBox>
-            <ListBoxItem ToolTip="This is a lonley toggle with TextBlock instead of icon">
+          <ListBox materialDesign:ListBoxAssist.CanUserToggleSelectedItem="True">
+            <ListBoxItem ToolTip="This is a lonely toggle with TextBlock instead of icon">
               <TextBlock Text="W" />
             </ListBoxItem>
           </ListBox>