Job completion-mode documentation has an unclarified note about a 'rare' condition

**This is a Bug Report**

**Problem:**
https://kubernetes.io/docs/concepts/workloads/controllers/job/#completion-mode mentions

> Note that, although rare, more than one Pod could be started for the same
> index, but only one of them will count towards the completion count.

Can it be clarified why that note is needed? And if the pod is started, will it run to completion, or aborted before running or ... ?

**Proposed Solution:**
@alculquicondor proposes via https://github.com/kubernetes/enhancements/issues/2214

> We can clarify that it will be aborted.

**Page to Update:**
https://kubernetes.io/docs/concepts/workloads/controllers/job

Start with the completion-mode section on the Job documentation page and read enhancement issue 2214 for the proposed clarification. Update the note so the behavior of the extra Pod is explicit, including that it will be aborted, and verify the page answers why the condition matters.

Written by the indexing model from the issue text.