eval: Port to agent2 (#40704)

Release Notes:

- N/A

crates/eval/src/examples/code_block_citations.rs

@@ -29,16 +29,19 @@ impl Example for CodeBlockCitations {
 
     async fn conversation(&self, cx: &mut ExampleContext) -> Result<()> {
         const FILENAME: &str = "assistant_tool.rs";
-        cx.push_user_message(format!(
-            r#"
-            Show me the method bodies of all the methods of the `Tool` trait in {FILENAME}.
-
-            Please show each method in a separate code snippet.
-            "#
-        ));
 
         // Verify that the messages all have the correct formatting.
-        let texts: Vec<String> = cx.run_to_end().await?.texts().collect();
+        let texts: Vec<String> = cx
+            .prompt(format!(
+                r#"
+                Show me the method bodies of all the methods of the `Tool` trait in {FILENAME}.
+
+                Please show each method in a separate code snippet.
+                "#
+            ))
+            .await?
+            .texts()
+            .collect();
         let closing_fence = format!("\n{FENCE}");
 
         for text in texts.iter() {