Register nested attributes

[sondrelg]

Code like this

import proj.app.enums

class Migration:
    enum=proj.app.enums.EnumClass

which is just a simplified example of a Django migration file, was flagging false positives.

The problem is that the current code does not register that proj.app.enums.EnumClass is related to the proj.app.enums import in any way.

I'm not super excited about this way of solving the problem, but this fixes the test example without breaking the existing test suite. Any feedback here, on how it might be cleaned up is much appreciated @JonasKs