add "token_logits_over_infill" in attr

Author: landajuela

protein_tune_rl/metrics/iglm_tokenwise_kl.py

@@ -127,6 +127,7 @@ def _fetch_logits_over_infill(
         """
         # Try a few attr names to keep this robust to minor refactors
         for attr in (
+            "token_logits_over_infill",  # preferred if available
             "logits",
             "get_logits",
             "token_logits",