docs: add or improve links to other sections

user_guide_src/source/changelogs/v4.1.5.rst

@@ -21,12 +21,12 @@ Enhancements
 ============
 
 - Added Cache config for reserved characters
-- The ``addForeignKey`` function of the ``Forge`` class can now define composite foreign keys in an array
+- The :ref:`addForeignKey()<adding-foreign-keys>` function of the ``Forge`` class can now define composite foreign keys in an array
 - The ``dropKey`` function of the ``Forge`` class can remove key
 - Now ``_`` can be used as separators in environment variable
 - Added Multiple filters for a route and Classname filter
 - Reduced memory usage of ``insertBatch()`` and ``updateBatch()``
-- Added Session based CSRF Protection
+- Added :ref:`Session based CSRF Protection <csrf-protection-methods>`
 - Added ``valid_url_strict`` rule for ``Validation``
 - Debug Toolbar
     - Added formatted query string to timeline

user_guide_src/source/dbmgmt/forge.rst

@@ -223,6 +223,7 @@ and unique keys with specific methods::
     $forge->addUniqueKey(['blog_id', 'uri']);
     // gives UNIQUE KEY `blog_id_uri` (`blog_id`, `uri`)
 
+.. _adding-foreign-keys:
 
 Adding Foreign Keys
 ===================

user_guide_src/source/incoming/routing.rst

@@ -354,6 +354,8 @@ can modify the generated routes, or further restrict them. The ``$options`` arra
     $routes->map($array, $options);
     $routes->group('name', $options, function ());
 
+.. _applying-filters:
+
 Applying Filters
 ----------------
 
@@ -390,7 +392,7 @@ You specify a filter classname for the filter value::
 
 **Multiple filters**
 
-.. important:: *Multiple filters* is disabled by default. Because it breaks backward compatibility. If you want to use it, you need to configure. See *Multiple filters for a route* in :doc:`/installation/upgrade_415` for the details.
+.. important:: *Multiple filters* is disabled by default. Because it breaks backward compatibility. If you want to use it, you need to configure. See :ref:`upgrade-415-multiple-filters-for-a-route` for the details.
 
 You specify an array for the filter value::
 

user_guide_src/source/installation/upgrade_415.rst

@@ -72,6 +72,8 @@ For optimization and a bug fix, the following behaviors, mostly used in testing,
 Breaking Enhancements
 =====================
 
+.. _upgrade-415-multiple-filters-for-a-route:
+
 Multiple filters for a route
 ----------------------------
 
@@ -99,7 +101,7 @@ The following methods and a property have been deprecated:
 - ``CodeIgniter\Router\RouteCollection::getFilterForRoute()``
 - ``CodeIgniter\Router\RouteCollection``'s property ``$filterInfo``
 
-See *Applying Filters* in :doc:`Routing </incoming/routing>` for the functionality.
+See :ref:`applying-filters` for the functionality.
 
 Project Files
 =============

user_guide_src/source/libraries/security.rst

@@ -29,6 +29,8 @@ Cross-site request forgery (CSRF)
 Config for CSRF
 ===============
 
+.. _csrf-protection-methods:
+
 CSRF Protection Methods
 -----------------------