[TASK] Type hint ext:fluid RenderingContext

The ext:fluid RenderingContext extends standalone fluid
RenderingContextInterface by adding getRequest(). This
object is always carried around in TYPO3 fluid universe.

When calling getRequest() in ViewHelpers, IDE's and
static analyzers don't know about this inheritance.
Unfortunately, we can't change standalone fluid at the
moment since that would be breaking, and we can't
change VH's method signatures either since that would
violate contravariance.

For now, we add a series on @var hints within various
ViewHelpers to make phpstan and IDE's more happy.

Resolves: #98378
Releases: main
Change-Id: I2cd8fc5962b2b8af3ce3fefabbae4e41577bb141
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75783


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>