[TASK] TYPO3 Coding Guidelines - TYPO3SniffPool.Commenting.DoubleSlashCommentsInNewLine

Change-Id: Ide409f59a9ece6f5e12fa06521c364078710135e
Resolves: #55123
Releases: 2.1
Reviewed-on: https://review.typo3.org/26914
Reviewed-by: Oliver Klee
Reviewed-by: Alex Kellner
Tested-by: Alex Kellner