Update form/form_customization.rst

Co-authored-by: Oskar Stark <oskarstark@googlemail.com>

Author: jmsche

form/form_customization.rst

@@ -87,12 +87,7 @@ control over how each form field is rendered, so you can fully customize them:
     Later in this article you can find the full reference of these Twig
     functions with more usage examples.
 
-.. _reference-forms-twig-field-name:
-.. _reference-forms-twig-field-value:
-.. _reference-forms-twig-field-label:
-.. _reference-forms-twig-field-help:
-.. _reference-forms-twig-field-errors:
-.. _reference-forms-twig-field-choices:
+.. _reference-forms-twig-field-helpers:
 
 Form Field Helpers
 ------------------