scorch zap merge optimize newDocNums lookup to outside of loop

And, also a "go fmt".

index/scorch/persister.go

@@ -68,7 +68,6 @@ OUTER:
 		persistWatchers = s.pausePersisterForMergerCatchUp(lastPersistedEpoch,
 			&lastMergedEpoch, persistWatchers)
 
-
 		var ourSnapshot *IndexSnapshot
 		var ourPersisted []chan error
 

index/scorch/segment/zap/merge.go

@@ -316,10 +316,12 @@ func persistMergedRest(segments []*SegmentBase, dropsIn []*roaring.Bitmap,
 				return nil, 0, err2
 			}
 
+			newDocNumsI := newDocNums[itrI]
+
 			postItr = postings.iterator(postItr)
 			next, err2 := postItr.Next()
 			for next != nil && err2 == nil {
-				hitNewDocNum := newDocNums[itrI][next.Number()]
+				hitNewDocNum := newDocNumsI[next.Number()]
 				if hitNewDocNum == docDropped {
 					return nil, 0, fmt.Errorf("see hit with dropped doc num")
 				}