Allow to change highlight via backend form (#40)

It was not possible to change the value of highlight for events due to
broken TCA.
This got fixed. The input is now streamlined to look the same as hidden
to not irritate users.

Relates: #10782

Configuration/TCA/tx_events_domain_model_event.php

@@ -232,9 +232,12 @@ return [
             'label' => $l10nPath . ':tx_events_domain_model_event.highlight',
             'config' => [
                 'type' => 'check',
+                'renderType' => 'checkboxToggle',
                 'items' => [
-                    '1' => [
-                        '0' => $l10nPathLang . ':labels.enabled',
+                    [
+                        0 => '',
+                        1 => '',
+                        'invertStateDisplay' => false,
                     ],
                 ],
                 'default' => 0,

Documentation/Changelog/3.5.2.rst

@@ -0,0 +1,30 @@
+3.5.2
+=====
+
+Breaking
+--------
+
+Nothing
+
+Features
+--------
+
+Nothing
+
+Fixes
+-----
+
+* Fix broken TCA for highlight property.
+  The highlight could not be saved.
+  An unexpected value (3) was submitted on selection.
+  We now migrated the property to look and act the same as hidden input.
+
+Tasks
+-----
+
+Nothing
+
+Deprecation
+-----------
+
+Nothing