I see some problems with this:
We'd have to auto detect when showing this link would be appropriate, if implemented. I'm a big fan of 'just in time' help, but applying it on a tag by tag basis is unruly, difficult to implement and difficult to maintain. Someone asking about traversing a doubly linked list would be completely uninterested in such a resource and the overhead to keep the 'noise' out unless appropriate is just too much work.
We would not be doing the resource a favor by linking given the sheer volume of questions where it might be appropriate to show. It would look like a sudden DDoS attack. Do we even want to link to resources that may or may not be available in the context of 'find help here instead?' It would need to come from something internal.
These questions aren't reference material for us unless they've been asked before, as things stand now.
The thing to do is leave a helpful comment and spread the word about the resource and add it to the related tag wiki info pages.
You don't have a bad idea, it's just too difficult and problematic to implement on a tag by tag basis. It's something the tag wiki system was designed to partly accomplish, by providing people a list of common questions and common resources, but people (for whatever reason) still fail to find them despite efforts to give them more visibility.
This provides information in a way where something doesn't jump out at a user saying "Nooo, use this resource instead of asking your question." By the time someone gets to the editor, the only thing that should slow them down is the list of related or possible duplicate questions that populates as they type. Adding some churn from the tag wiki system to that mix (a resource we control and curate) would make a lot more sense.