[BUGFIX] Fix typos in EmailFinisher

This fixes some typos to make the comments more readable.

Resolves: #88584
Releases: master, 9.5
Change-Id: I165a80f2f4d82c1090f4413140c6b584c7b93ecd
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61414


Reviewed-by: Maik Peuser <maik.peuser@verdure.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>