Nullable promise parameter not parsed correctly

[mvano]

When IDL indicates a nullable promise parameter, respec does not link the param type at all. In the example below, I would expect it to link Foo to its definition, excluding the question mark.

Promise<Foo?>    getFoo ();

I ran into this with the Push API spec for getSubscription: https://w3c.github.io/push-api/#pushmanager-interface

[marcoscaceres]

wfm.. might have been an old school idl problem