Use trash-rs' is_empty more

Fixes two instances where enumerating trash items isn't needed.

src/menu.rs

@@ -160,7 +160,7 @@ pub fn context_menu<'a>(
         ) => {
             if selected_trash_only {
                 children.push(menu_item(fl!("open"), Action::Open).into());
-                if tab::trash_entries() > 0 {
+                if !trash::os_limited::is_empty().unwrap_or(true) {
                     children.push(menu_item(fl!("empty-trash"), Action::EmptyTrash).into());
                 }
             } else if let Some(entry) = selected_desktop_entry {