ARROW-9585: [Rust][DataFusion] Remove duplicated to-do line
ARROW-9585: [Rust][DataFusion] Remove duplicated to-do line

Looks like a copy-paste error perhaps; I can't imagine it's intentional.
cpcloud/arrow,cpcloud/arrow,apache/arrow,apache/arrow,apache/arrow,xhochy/arrow,laurentgo/arrow,kou/arrow,kou/arrow,kou/arrow,icexelloss/arrow,icexelloss/arrow,apache/arrow,wesm/arrow,apache/arrow,icexelloss/arrow,kou/arrow,kou/arrow,apache/arrow,cpcloud/arrow,laurentgo/arrow,icexelloss/arrow,laurentgo/arrow,wesm/arrow,kou/arrow,cpcloud/arrow,wesm/arrow,xhochy/arrow,icexelloss/arrow,cpcloud/arrow,xhochy/arrow,xhochy/arrow,xhochy/arrow,apache/arrow,icexelloss/arrow,wesm/arrow,cpcloud/arrow,xhochy/arrow,icexelloss/arrow,kou/arrow,icexelloss/arrow,cpcloud/arrow,icexelloss/arrow,wesm/arrow,xhochy/arrow,apache/arrow,xhochy/arrow,xhochy/arrow,icexelloss/arrow,icexelloss/arrow,xhochy/arrow,laurentgo/arrow,laurentgo/arrow,kou/arrow,icexelloss/arrow,kou/arrow,xhochy/arrow,xhochy/arrow,wesm/arrow,apache/arrow,kou/arrow,cpcloud/arrow,xhochy/arrow,apache/arrow,xhochy/arrow,kou/arrow,cpcloud/arrow,laurentgo/arrow,wesm/arrow,laurentgo/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow,kou/arrow,kou/arrow,apache/arrow,laurentgo/arrow,apache/arrow,wesm/arrow,cpcloud/arrow,wesm/arrow,icexelloss/arrow,apache/arrow,cpcloud/arrow,cpcloud/arrow,laurentgo/arrow,cpcloud/arrow,kou/arrow,wesm/arrow,wesm/arrow,icexelloss/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow,xhochy/arrow,apache/arrow,cpcloud/arrow,laurentgo/arrow,laurentgo/arrow,wesm/arrow