Add remaining characters to seo description

That feature is provided by TYPO3.
The feature is triggered by max option.
Even if meta description has no official max length, I use 200 to get a
feeling for actual length as editor.
yoast recommends 120 - 156, see: https://yoast.com/meta-descriptions/

Configuration/TCA/Overrides/pages.php

@@ -17,6 +17,12 @@
                     'eval' => 'date,int',
                 ],
             ],
+            'description' => [
+                'config' => [
+                    'max' => 200,
+                ],
+            ],
         ],
     ]);
+
 })('ds_site', 'pages');