doc: releases: resolved issues for v3.1.0

Follow along with the release checklist (#43286) like this:

$ ./scripts/release/list_issues.py -o zephyrproject-rtos -r zephyr -s
2022-02-22 -f issues.txt

Then copy issues.txt into the right place in the doc, and clean up the
resulting .rst errors by properly escaping and converting the markdown
format used in github issue titles.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>