RangefuncExperiment: make Backwards copy-pastable and link issues

Change-Id: If88d2dff0132b1d9382956d053ca728820039aa0
Reviewed-on: https://go-review.googlesource.com/c/wiki/+/550675
Reviewed-by: Yann Salaün <yannsalaun1@gmail.com>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Auto-Submit: Matt Layher <mdlayher@gmail.com>