[DOCS] Add example for finisher option "recipients"

The new option is explained here:
https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/10.0/Featur
e-80420-AllowMultipleRecipientsInEmailFinisher.html

Releases: main, 11.5
Resolves: #96086
Change-Id: I740e360735e09d07f5a6f16513317e4b226fd0b1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74937


Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>