service/ci: document the name of the cache bucket

service/ci.md

@@ -509,9 +509,9 @@ seconds, technically) [rate limit](https://www.docker.com/increase-rate-limits/)
 
 In order to increase the efficiency of the GitLab CI caching mechanism, job
 caches configured via the `cache:` key in `.gitlab-ci.yml` are uploaded to
-[object storage](service/object-storage) at the end of jobs. This means that it
-doesn't matter on which runner a job is run, it will always get the latest copy
-of its cache.
+[object storage](service/object-storage) at the end of jobs, in the
+`gitlab-ci-runner-cache` bucket. This means that it doesn't matter on which
+runner a job is run, it will always get the latest copy of its cache.
 
 This feature is enabled via the runner instance configuration located in
 `/etc/gitlab-runner/config.toml`, and is also configured on the OSUOSL-hosted