zeta2: Update prompts to match training more closely (#40383)

Release Notes:

- N/A

crates/edit_prediction_context/src/edit_prediction_context.rs

@@ -27,6 +27,7 @@ pub use predict_edits_v3::Line;
 #[derive(Clone, Debug, PartialEq)]
 pub struct EditPredictionContextOptions {
     pub use_imports: bool,
+    pub use_references: bool,
     pub excerpt: EditPredictionExcerptOptions,
     pub score: EditPredictionScoreOptions,
 }
@@ -116,19 +117,23 @@ impl EditPredictionContext {
             index_state,
         )?;
         let excerpt_text = excerpt.text(buffer);
-        let excerpt_occurrences = text_similarity::Occurrences::within_string(&excerpt_text.body);
 
-        let adjacent_start = Point::new(cursor_point.row.saturating_sub(2), 0);
-        let adjacent_end = Point::new(cursor_point.row + 1, 0);
-        let adjacent_occurrences = text_similarity::Occurrences::within_string(
-            &buffer
-                .text_for_range(adjacent_start..adjacent_end)
-                .collect::<String>(),
-        );
+        let declarations = if options.use_references
+            && let Some(index_state) = index_state
+        {
+            let excerpt_occurrences =
+                text_similarity::Occurrences::within_string(&excerpt_text.body);
 
-        let cursor_offset_in_file = cursor_point.to_offset(buffer);
+            let adjacent_start = Point::new(cursor_point.row.saturating_sub(2), 0);
+            let adjacent_end = Point::new(cursor_point.row + 1, 0);
+            let adjacent_occurrences = text_similarity::Occurrences::within_string(
+                &buffer
+                    .text_for_range(adjacent_start..adjacent_end)
+                    .collect::<String>(),
+            );
+
+            let cursor_offset_in_file = cursor_point.to_offset(buffer);
 
-        let declarations = if let Some(index_state) = index_state {
             let references = get_references(&excerpt, &excerpt_text, buffer);
 
             scored_declarations(
@@ -195,6 +200,7 @@ mod tests {
                     buffer_snapshot,
                     EditPredictionContextOptions {
                         use_imports: true,
+                        use_references: true,
                         excerpt: EditPredictionExcerptOptions {
                             max_bytes: 60,
                             min_bytes: 10,