docs: Improve watch_code_prompt instructions

aider/watch_prompts.py

@@ -1,8 +1,9 @@
 watch_code_prompt = """
-Find the "AI" comments below (marked with █) in the code files I've shared with you.
-I've written your instructions there.
-Follow my instructions as given in the AI comments and make the requested changes.
-Also, be sure to remove all the "AI" comments from the code too.
+I've written your instructions in comments in the code and marked them with "ai"
+You can see the "AI" comments shown below (marked with █).
+Find them in the code files I've shared with you, and follow their instructions.
+
+After completing those instructions, also be sure to remove all the "AI" comments from the code too.
 """
 
 watch_ask_prompt = """/ask