How can I trigger an event when the user executes a cell with `?`?

Hi all,

Does anyone know a good way of listening for the user to submit a ? or a ??? I’d like to trigger an event (say, open a new MainAreaWidget) when a user executes a code cell with ? or ??. I’ve thought about trying to use @jupyterlab/inspector, but I’m not really looking to inspect the code under the cursor - I’m really just looking to trigger an event whenever the user sends <something>? or <something else>??.

(Sorry if you’ve seen a similar message already on gitter - I wanted to post here too in case my other message gets buried.)