Allow annotating import calls

[hlascelles]

We would like to annotate our imports using the Rails annotate method.

Things.annotate("NOTE_ME").scoping do
  Things.import!(stuff)
end

->

INSERT INTO ..... /* NOTE_ME */"

We are seeing that the annotation does not get used. I've had a look, but can't see an immediate reason. Is this something that is obvious to solve? If not I can look further.