Update app.py

Further updating doc string to see if the agent incorporates it properly

app.py

@@ -27,6 +27,7 @@ def webpage_contents_get(url:str, headers_in: dict = None)-> str: #it's import t
     #Keep this format for the description / args / args description but feel free to modify the tool
     """A simple function to grab contents of a webpage.  As this is very long and not easily interpretable,
     summaries based on other tools applied to this content should be returned to users with questions.
+    Printing the value returned from this function is not acceptable.
     Args:
         url: The URL the contents of which the tool will get
         headers_in: A dictionary which defines the headers for the request.  Defaults to None