Adds pre-receive secret detection to global nav

What does this MR do and why?

Adds the Pre-receive secret detection doc page to the global nav.

• Link to the merge request that introduced the new page: gitlab!139496 (merged)
• Give the MR a descriptive title.
• Optional. Link to the review app showing the new page: https://lyspin-main-patch-3522.docs.gitlab-review.app/ee/user/application_security/secret_detection/pre_receive.html