docs: add links to upgrade instructions in Upgrading pages

Author: kenjis

user_guide_src/source/installation/upgrade_404.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.0.x to 4.0.4
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 CodeIgniter 4.0.4 fixes a bug in the implementation of :doc:`Controller Filters </incoming/filters>`, breaking
 code implementing the ``FilterInterface``.
 

user_guide_src/source/installation/upgrade_405.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.0.4 to 4.0.5
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 **Cookie SameSite support**
 
 CodeIgniter 4.0.5 introduces a setting for the cookie SameSite attribute. Prior versions did not set this

user_guide_src/source/installation/upgrade_410.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.0.5 to 4.1.0 or 4.1.1
 ######################################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 **Legacy Autoloading**
 
 `Autoloader::loadLegacy()` method was originally for transition to CodeIgniter v4. Since `4.1.0`,

user_guide_src/source/installation/upgrade_412.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.1.1 to 4.1.2
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 **current_url() and indexPage**
 
 Due to `a bug <https://github.com/codeigniter4/CodeIgniter4/issues/4116>`_ in ``current_url()``,

user_guide_src/source/installation/upgrade_413.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.1.2 to 4.1.3
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 **Cache TTL**
 
 There is a new value in **app/Config/Cache.php**: ``$ttl``. This is not used by framework

user_guide_src/source/installation/upgrade_414.rst

@@ -2,6 +2,16 @@
 Upgrading from 4.1.3 to 4.1.4
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
+.. contents::
+    :local:
+    :depth: 2
+
 This release focuses on code style. All changes (except those noted below) are cosmetic to bring the code in line with the new
 `CodeIgniter Coding Standard <https://github.com/CodeIgniter/coding-standard>`_ (based on PSR-12).
 

user_guide_src/source/installation/upgrade_415.rst

@@ -2,6 +2,12 @@
 Upgrading from 4.1.4 to 4.1.5
 #############################
 
+Please refer to the upgrade instructions corresponding to your installation method.
+
+- :ref:`Composer Installation App Starter Upgrading <app-starter-upgrading>`
+- :ref:`Composer Installation Adding CodeIgniter4 to an Existing Project Upgrading <adding-codeigniter4-upgrading>`
+- :ref:`Manual Installation Upgrading <installing-manual-upgrading>`
+
 .. contents::
     :local:
     :depth: 2