docstring typo

Author: Paul McMillan

flask/app.py

@@ -1446,7 +1446,7 @@ def create_url_adapter(self, request):
 
         .. versionchanged:: 0.9
            This can now also be called without a request object when the
-           UR adapter is created for the application context.
+           URL adapter is created for the application context.
         """
         if request is not None:
             return self.url_map.bind_to_environ(request.environ,