feat: make columnar menu traversal direction configurable (#951)

* Make columnar menu traversal direction configurable

* Add tests for columnar menu selection position updates

* Apply changes based on review

Author: simonborje

src/lib.rs

@@ -278,7 +278,7 @@ pub use validator::{DefaultValidator, ValidationResult, Validator};
 mod menu;
 pub use menu::{
     menu_functions, ColumnarMenu, DescriptionMenu, DescriptionMode, IdeMenu, ListMenu, Menu,
-    MenuBuilder, MenuEvent, MenuTextStyle, ReedlineMenu,
+    MenuBuilder, MenuEvent, MenuTextStyle, ReedlineMenu, TraversalDirection,
 };
 
 mod terminal_extensions;