[BUGFIX] Correct reference to backend layout chapter in TYPO3 Explain…

…ed (#1095)

Sphinx is here lax and looks, if there is a reference of that name in all of the
intersphinxes. But guides is more picky and throws a warning. Therefore, the
reference is now prefixed with the correct manual.

Releases: main, 12.4

Documentation/Conditions/Index.rst

@@ -147,7 +147,7 @@ tree.pagelayout
 
     :Data type: Integer / String
 
-    Check for the defined :ref:`backend layout <be-layout>` of a page, including
+    Check for the defined :ref:`backend layout <t3coreapi:be-layout>` of a page, including
     the inheritance of the field `Backend Layout (subpages of this page)`.
 
     Example: