[1.7.x] Fixed typo in docs/topics/testing/tools.txt.

Backport of 7ce4ef58c9 from master
Revert "[1.7.x] Fixed #23088 -- Used `six` `range` type in `Paginator.page_range`."

This reverts commit ce95ab8f025cc9f35990f0c2d9a290eec1ece753.

It caused some backwards compatibility concerns (refs #23140).