Documentation for Move to start/end of list actions on board items

What does this MR do and why?

Documentation for #367473 (closed)

Screenshots or screen recordings

Targeted feature

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

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 #367473 (closed)