Fix build

Author: wouterj

form/create_custom_field_type.rst

@@ -164,7 +164,7 @@ link for details), create a ``gender_widget`` block to handle this:
 .. note::
 
     Make sure the correct widget prefix is used. In this example the name should
-    be ``gender_widget`` (see :ref:`cookbook-form-customization-form-themes`).
+    be ``gender_widget`` (see :ref:`form-customization-form-themes`).
     Further, the main config file should point to the custom form template
     so that it's used when rendering all forms.
 

form/form_themes.rst

@@ -177,7 +177,7 @@ override the default error rendering for *all* fields, copy and customize the
 .. index::
    single: Forms; Global Theming
 
-.. _book-forms-theming-global:
+.. _forms-theming-global:
 
 Global Form Theming
 -------------------
@@ -186,7 +186,7 @@ In the above example, you used the ``form_theme`` helper (in Twig) to "import"
 the custom form fragments into *just* that form. You can also tell Symfony
 to import form customizations across your entire project.
 
-.. _book-forms-theming-twig:
+.. _forms-theming-twig:
 
 Twig
 ....