Missing Generic Type Parameter shows quick fix for redundant namespace

Source:

``` C#
using System.Collections.Generic;
class X : IEnumerable
```

The word `IEnumerable` will correctly show quick fixes for `using System.Collections` and `System.Collections.`.

It will also show a quickfix for `System.Collections.Generic.`, even though that is redundant and doesn't fix the error.  (it does not show the corresponding `using` quick fix)
