Clarify usage of `ref` attribute

What does this MR do?

Serves as a follow-up to !38287 (closed) which could not pass CI due to a lack of capitalization in the commit message. Rather than 🏓 with the community contributor, I've run git commit --amend against the commit, and force-pushed. That resulted in this MR.

Goal: get the work submitted in !38287 (closed) merged with the least amount of frustration for @loru88.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability 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
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team