[DOCS] Add documentation for sys_note

Resolves: #102056
Releases: main, 12.4
Change-Id: Ie19e70148b893aff2e82f6ef2ed1e5b31f39407a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82244


Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Chris Müller <typo3@krue.ml>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Lina Wolf <112@linawolf.de>
Tested-by: Chris Müller <typo3@krue.ml>
Tested-by: Lina Wolf <112@linawolf.de>