Doc updates: requeueing batched background migrations

What does this MR do and why?

• I got a bit confused when doing this for a recent MR:!123002 (merged)
• I once requeued a job with a different approach that was recommende in Slack without realizing we had these docs: !107701 (merged)
• #385352 (closed)

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.