[DOCS] Improve the validator documentation for editors

This patch optimizes the wording of the documentation
and adds links to other documents.

While being on it, images and their corresponding
captions have been fixed throughout the documentation.

Resolves: #97825
Releases: main
Change-Id: I6d783477e9dcf0ba31c34b7f3d9dae79049d173b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74994


Tested-by: core-ci <typo3@b13.com>
Tested-by: Elias Häußler <e.haeussler@familie-redlich.de>
Tested-by: waldhacker <hello@waldhacker.dev>
Reviewed-by: Elias Häußler <e.haeussler@familie-redlich.de>
Reviewed-by: waldhacker <hello@waldhacker.dev>