[TASK] Improve comment of GeneralUtility::makeInstance()

A note about the fact, that ObjectManager::get() is injecting
dependencies may be helpful.

Resolves: #61916
Releases: master
Change-Id: I4067036ae5d95877245e150c9f7ca91dea3c954e
Reviewed-on: http://review.typo3.org/32991
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>