Centralize logic around which keybind to display (#25215)

Closes #24931

We've flipped back and forth at least once on whether the last or first
added keybinding should be shown in different contexts (See
[this](https://github.com/zed-industries/zed/issues/23621#issuecomment-2614061385)
as well as #23621 and the subsequent #23660)

This PR attempts to pick a side to stick with so that we are at least
consistent until #23660 is resolved and we have a way to determine which
keybinds to display in a manner that is both consistent and not
confusing

Release Notes:

- N/A

crates/gpui/src/platform/mac/platform.rs

@@ -290,15 +290,10 @@ impl MacPlatform {
                 action,
                 os_action,
             } => {
-                // Note that this is not the standard logic for selecting which keybinding to
-                // display. Typically the last binding takes precedence for display. However, in
-                // this case the menus are not updated on context changes. To make these bindings
-                // more likely to be correct, the first binding instead takes precedence (typically
-                // from the base keymap).
-                let keystrokes = keymap
-                    .bindings_for_action(action.as_ref())
-                    .next()
-                    .map(|binding| binding.keystrokes());
+                let keystrokes = crate::Keymap::binding_to_display_from_bindings(
+                    keymap.bindings_for_action(action.as_ref()),
+                )
+                .map(|binding| binding.keystrokes());
 
                 let selector = match os_action {
                     Some(crate::OsAction::Cut) => selector("cut:"),