[DOCS] Fix wrong reference to global REQUEST_TYPE

There is no global variable named REQUEST_TYPE,
it is called TYPO3_REQUEST.

Releases: master
Resolves: #93206
Related: #92947
Change-Id: I86d3c2f8306744f41cfa504f4a42490f4b8eaa6a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67330
Tested-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/core/Documentation/Changelog/11.0/Deprecation-92947-DeprecateTYPO3_MODEAndTYPO3_REQUESTTYPEConstants.rst

@@ -168,7 +168,7 @@ is called before a controller action is executed. It should be noted that fallin
 :php:`$GLOBALS['TYPO3_REQUEST']` is a technical debt in itself, the TYPO3 core will try to reduce the need
 for this fallback over time. A call using this fallback looks like::
 
-    if (ApplicationType::fromRequest($GLOBALS['REQUEST_TYPE'])->isFrontend())
+    if (ApplicationType::fromRequest($GLOBALS['TYPO3_REQUEST'])->isFrontend())
         ...
     }