Split DuplicateLine into DuplicateLineUp and DuplicateLineDown (#9715)

Fixes #9601

Release Notes:
- `DuplicateLine` is now split into `DuplicateLineUp` and
`DuplicateLineDown`

crates/zed/src/zed/app_menus.rs

@@ -98,10 +98,7 @@ pub fn app_menus() -> Vec<Menu<'static>> {
                 MenuItem::separator(),
                 MenuItem::action("Move Line Up", editor::actions::MoveLineUp),
                 MenuItem::action("Move Line Down", editor::actions::MoveLineDown),
-                MenuItem::action(
-                    "Duplicate Selection",
-                    editor::actions::DuplicateLine::default(),
-                ),
+                MenuItem::action("Duplicate Selection", editor::actions::DuplicateLineDown),
             ],
         },
         Menu {