Add anchors to ExtTables.rst (#5829)

Releases: main, 13.4, 12.4

Author: linawolf

Documentation/ExtensionArchitecture/FileStructure/ExtTables.rst

@@ -30,6 +30,8 @@
         :ref:`Configuration/TCA/ <extension-configuration-tca>`.
 
 
+..  _ext-tables-php-not-use:
+
 Should not be used for
 ======================
 
@@ -44,6 +46,8 @@ Should not be used for
     as this might break the frontend. They should go in
     :file:`Configuration/TCA/Overrides/sys_template.php`
 
+..  _ext-tables-php-usage:
+
 Should be used for
 ==================
 
@@ -54,6 +58,8 @@ These are the typical functions that should be placed inside :file:`ext_tables.p
 *  Registration of :ref:`custom page types <page-types-example>`
 *  Extending the :ref:`Backend user settings <user-settings-extending>`
 
+..  _ext-tables-php-examples:
+
 Examples
 ========