Add helpful self-review comments to MRs

What does this MR do and why?

Help make a more pleasant review process and decrease time to merge. I have frequently been told my self-review comments were helpful, so perhaps we can encourage that more?

Making helpful self-review comments:

• reduces cognitive load on reviewer in understanding the area of code they are reviewing
• reduce back and forth that can happen for things like Hey did you think of this way - if you state your decision process and things you considered, it may reduce those type of cycles if the reviewer sees you have already considered something.
• help in understanding tradeoffs that were taken on a certain place in the code and why
  • this can be thought of as an extension of the MR description, but more focused on a specific part of the code.

context: !80518 (comment 868834570)

Related to #354923

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.