Prompt for collaborator generation when type hint is wrongly namespaced

[ciaranmcnulty]

If a user forgets to use a namespace for their dependency when type hinting it:

namespace spec\MyProject

class FooSpec extends ObjectBehaviour
{
    function it_does_a_thing(Collab $collab)
    {

    }
}

Currently we detect that it starts with the spec namespace and silently ignore it.

It would be better to alert the user what's going on (maybe some sort of better error message?), or even better prompt them and change the namespace in the spec file on their behalf