`warn` -> `print` for consistency

IPython/terminal/interactiveshell.py

@@ -914,7 +914,7 b' class TerminalInteractiveShell(InteractiveShell):'
     active_eventloop = None
     def enable_gui(self, gui=None):
         if self._inputhook is not None and gui is not None:
-            warn(
+            print(
                 f"Shell was already running a gui event loop for {self.active_eventloop}; switching to {gui}."
             )
         if gui and (gui not in {"inline", "webagg"}):