fix: Add more clear instruction to the doc updater agent about one PR for each recommended change

PiperOrigin-RevId: 817831087

Author: xuanyang15

contributing/samples/adk_documentation/adk_docs_updater/agent.py

@@ -85,7 +85,15 @@
         - Use active voice phrasing in your doc updates.
         - Use second person "you" form of address in your doc updates.
       9. Create pull requests to update the ADK doc file using the `create_pull_request_from_changes` tool.
-        - For each recommended change, create a separate pull request.
+        - For each recommended change, create a separate pull request. Make sure the recommended change has exactly one pull request.
+          For example, if the ADK doc issue contains the following 2 recommended changes:
+          ```
+          1. Title of recommended change 1
+             <content of recommended change 1>
+          2. Title of recommended change 2
+             <content of recommended change 2>
+          ```
+          Then you should create 2 pull requests, one for each recommended change, even if each recommended change needs to update multiple ADK doc files.
         - The title of the pull request should be "Update ADK doc according to issue #<issue number> - <change id>", where <issue number> is the number of the ADK docs issue and <change id> is the id of the recommended change (e.g. "1", "2", etc.).
         - The body of the pull request should be the instructions about how to update the ADK docs.
         - **{APPROVAL_INSTRUCTION}**