update prompts

Author: alexcheng1982

examples/src/main/resources/prompt_template/code-generator/evaluation.st

@@ -5,4 +5,5 @@ Requirements:
 - Ensure the code follows good naming conventions.
 - The code is passed if all criteria are met with no improvements needed.
 
+**Code**
 {code}

examples/src/main/resources/prompt_template/code-generator/initial-result.st

@@ -1,3 +1,4 @@
-Goal: Generate Java code to complete the task based on the input.
+Goal: Generate Java code to complete the task based on the input. Output *only* the code. No explanations.
 
+**Task**
 {input}

examples/src/main/resources/prompt_template/code-generator/optimization.st

@@ -1,10 +1,10 @@
-Goal: Improve existing code based on feedback.
+Goal: Improve existing code based on feedback. Output *only* the code. No explanations.
 
-Requirements:
+**Requirements**
 - Address all concerns in the feedback.
 
-Code:
+**Code**
 {code}
 
-Feedback:
+**Feedback**
 {feedback}