Fix function call for redirects task

Fix for a problem reported at: technical-writing#675 (comment 1102517618).

This function is also called here: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/a94b6a8804d0261a97371458f75134d3421d74d5/lib/tasks/redirects.rake#L90, where it is correctly called.

CC @aqualls