add feature name into module and update position weighted to match dper2
Test Plan:
The notebook showed no diff for id score list
https://our.intern.facebook.com/intern/anp/view/?id=154764
Reviewed By: alyssawangqq
Differential Revision: D17649974
fbshipit-source-id: 84cb4ae372fc215295c2d0b139d65f4eacafae4a
