Fix wording of Cycle Analytics stage legends

These are legends for the lists of objects related to the different Cycle Analytics stages, like on https://gitlab.com/gitlab-com/www-gitlab-com/cycle_analytics. Relative made little sense and should be Related.

approved this merge request

enabled an automatic merge when the pipeline for 897f98cc succeeds

added ~1434245 cycle analytics labels

mentioned in merge request !10669 (merged)

canceled the automatic merge

merged

mentioned in commit bacf652a