eth: updated comments (#21490)

eth/bloombits.go

@@ -137,7 +137,7 @@ func (b *BloomIndexer) Commit() error {
 	return batch.Write()
 }
 
-// PruneSections returns an empty error since we don't support pruning here.
+// Prune returns an empty error since we don't support pruning here.
 func (b *BloomIndexer) Prune(threshold uint64) error {
 	return nil
 }