Update app.py

Formatting docstring

app.py

@@ -150,7 +150,7 @@ def summarize_and_answer_from_web(url: str, question:str) -> str:
 def tool_visit_webpage(url:str) -> str:
     '''
     A tool used to visit a webpage, and return the appropriate information from it
-    Args
+    Args:
       url: A string url, the site to be visited
     '''
     vst = VisitWebpageTool()