[DOCS] Correct example for htmlSupport in RTE CKEditor

The main key is not "RTE" in YAML, but "editor".

Resolves: #103678
Releases: main, 12.4
Change-Id: I3c09ac3f0071be70ba3fb6c130653b8b75dc98b4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83931
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/rte_ckeditor/Documentation/Configuration/_Examples/_AllowSpecificTag.yaml

@@ -1,5 +1,5 @@
 # Allow the <iframe> tag with all attributes, all classes and all styles:
-RTE:
+editor:
   config:
     htmlSupport:
       allow: