[DOCS] Distinguish composer and legacy installation in cron examples

Releases: main, 11.5
Resolves: #97965
Change-Id: I6e03354925b4ecb9c3f72554862a01057851f48b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75237


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>