[DOCS] Fix formatting in Webp changelog

Releases: main
Resolves: #103507
Change-Id: I571d99521ffa1e36b9cb18cb1621132d70f6382b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83628


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