Added example messages to wholefile edit format

aider/coders/base_prompts.py

@@ -8,3 +8,5 @@ class CoderPrompts:
     files_content_local_edits = "I edited the files myself."
 
     lazy_prompt = ""
+
+    example_messages = []

aider/coders/wholefile_prompts.py

@@ -14,18 +14,43 @@ Once you understand the request you MUST:
 3. If changes are needed, output a copy of each file that needs changes.
 """
 
+    example_messages = [
+        dict(
+            role="user",
+            content="Change the greeting to be more casual",
+        ),
+        dict(
+            role="assistant",
+            content="""Ok, I will:
+
+1. Switch the greeting text from "Hello" to "Hey".
+
+show_greeting.py
+{fence[0]}
+import sys
+
+def greeting(name):
+    print(f"Hey {name}")
+
+if __name__ == '__main__':
+    greeting(sys.argv[1])
+{fence[1]}
+""",
+        ),
+    ]
+
     system_reminder = """To suggest changes to a file you MUST return the entire content of the updated file.
 You MUST use this *file listing* format:
 
 path/to/filename.js
-{fence[0]}javascript
+{fence[0]}
 // entire file content ...
 // ... goes in between
 {fence[1]}
 
 Every *file listing* MUST use this format:
 - First line: the filename with any originally provided path
-- Second line: opening {fence[0]} including the code language
+- Second line: opening {fence[0]}
 - ... entire content of the file ...
 - Final line: closing {fence[1]}