Change comments to point to the new path of sidekiq-cluster

What does this MR do?

sidekiq-cluster is moved from bin/ to ee/bin/ in EE code as a result all references to it should change as well. Please see https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/11001. This MR contains corresponding changes in CE. The changes are trivial and limited to comments. No other change has been made.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers