[BUGFIX] 13.4: addPiFlexFormValue needs '*' to match all content elements otherwise nothing will be displayed (#6421)

Author: Tim-Obert

Documentation/ApiOverview/FlexForms/_codesnippets/_extbase_plugin.php

@@ -20,7 +20,7 @@
 );
 
 ExtensionManagementUtility::addPiFlexFormValue(
-    '',
+    '*',
     'FILE:EXT:myext/Configuration/FlexForms/MyFlexform.xml',
     $ctypeKey,
 );

Documentation/ApiOverview/FlexForms/_codesnippets/_plain_plugin.php

@@ -21,7 +21,7 @@
 );
 
 ExtensionManagementUtility::addPiFlexFormValue(
-    '',
+    '*',
     'FILE:EXT:myext/Configuration/FlexForms/MyFlexform.xml',
     $ctypeKey,
 );