Inline Assist: replace "accept" action on generation error with "restart" (#15476)

Release Notes:

- N/A

crates/assistant/src/inline_assistant.rs

@@ -1219,7 +1219,8 @@ impl EventEmitter<PromptEditorEvent> for PromptEditor {}
 impl Render for PromptEditor {
     fn render(&mut self, cx: &mut ViewContext<Self>) -> impl IntoElement {
         let gutter_dimensions = *self.gutter_dimensions.lock();
-        let buttons = match &self.codegen.read(cx).status {
+        let status = &self.codegen.read(cx).status;
+        let buttons = match status {
             CodegenStatus::Idle => {
                 vec![
                     IconButton::new("cancel", IconName::Close)
@@ -1272,7 +1273,7 @@ impl Render for PromptEditor {
                         .on_click(
                             cx.listener(|_, _, cx| cx.emit(PromptEditorEvent::CancelRequested)),
                         ),
-                    if self.edited_since_done {
+                    if self.edited_since_done || matches!(status, CodegenStatus::Error(_)) {
                         IconButton::new("restart", IconName::RotateCw)
                             .icon_color(Color::Info)
                             .shape(IconButtonShape::Square)