gpui: Improve window.prompt to support ESC with non-English cancel text on macOS (#29538)

Release Notes:

- N/A

----

The before version GPUI used `Cancel` for cancel text, if we use
non-English text (e.g.: "取消" in Chinese), then the press `Esc` to cancel
will not work.

So this PR to change it by use `PromptButton` to instead the `&str`,
then we can use `PromptButton::cancel("取消")` for the `Cancel` button.

Run `cargo run -p gpui --example window` to test.

---

Platform Test:

- [x] macOS
- [x] Windows
- [x] Linux (x11 and Wayland)

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>

crates/gpui/src/platform.rs

@@ -418,7 +418,7 @@ pub(crate) trait PlatformWindow: HasWindowHandle + HasDisplayHandle {
         level: PromptLevel,
         msg: &str,
         detail: Option<&str>,
-        answers: &[&str],
+        answers: &[PromptButton],
     ) -> Option<oneshot::Receiver<usize>>;
     fn activate(&self);
     fn is_active(&self) -> bool;
@@ -1244,6 +1244,58 @@ pub enum PromptLevel {
     Critical,
 }
 
+/// Prompt Button
+#[derive(Clone, Debug, PartialEq)]
+pub enum PromptButton {
+    /// Ok button
+    Ok(SharedString),
+    /// Cancel button
+    Cancel(SharedString),
+    /// Other button
+    Other(SharedString),
+}
+
+impl PromptButton {
+    /// Create a button with label
+    pub fn new(label: impl Into<SharedString>) -> Self {
+        PromptButton::Other(label.into())
+    }
+
+    /// Create an Ok button
+    pub fn ok(label: impl Into<SharedString>) -> Self {
+        PromptButton::Ok(label.into())
+    }
+
+    /// Create a Cancel button
+    pub fn cancel(label: impl Into<SharedString>) -> Self {
+        PromptButton::Cancel(label.into())
+    }
+
+    #[allow(dead_code)]
+    pub(crate) fn is_cancel(&self) -> bool {
+        matches!(self, PromptButton::Cancel(_))
+    }
+
+    /// Returns the label of the button
+    pub fn label(&self) -> &SharedString {
+        match self {
+            PromptButton::Ok(label) => label,
+            PromptButton::Cancel(label) => label,
+            PromptButton::Other(label) => label,
+        }
+    }
+}
+
+impl From<&str> for PromptButton {
+    fn from(value: &str) -> Self {
+        match value.to_lowercase().as_str() {
+            "ok" => PromptButton::Ok("Ok".into()),
+            "cancel" => PromptButton::Cancel("Cancel".into()),
+            _ => PromptButton::Other(SharedString::from(value.to_owned())),
+        }
+    }
+}
+
 /// The style of the cursor (pointer)
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, JsonSchema)]
 pub enum CursorStyle {