Fix links to product features

What does this MR do?

Pages moving on about.gitlab.com caused broken links in documentation.

This fixes two of the broken links.

Related issues

Relates to: https://gitlab.com/gitlab-org/gitlab-ce/issues/51696.

Author's checklist

• Apply the correct labels and milestone

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards