Add link to a feedback issue

What does this MR do and why?

Add the link to the branch rules feedback issue

Screenshots or screen recordings

How to set up and validate locally

1. Enable :branch_rules FF locally
2. Settings - Repository - Branch rules
3. Make sure link is clickable and leads to #388149

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #391455 (closed)