docs: improve configuration.rst

user_guide_src/source/database/configuration.rst

@@ -105,6 +105,8 @@ within the class' constructor:
 
 .. literalinclude:: configuration/008.php
 
+.. _database-config-with-env-file:
+
 **************************
 Configuring with .env File
 **************************

user_guide_src/source/general/configuration.rst

@@ -183,6 +183,10 @@ are considered for merging into the configuration object's properties.
 .. important:: You cannot add a new property by setting environment variables,
     nor change a scalar value to an array. See :ref:`env-var-replacements-for-data`.
 
+.. note:: This feature is implemented in the ``CodeIgniter\Config\BaseConfig``
+    class. So it will not work with a few files in the **app/Config** folder
+    that do not extends the class.
+
 If the prefix of a namespaced variable exactly matches the namespace of the configuration
 class, then the trailing part of the setting (after the dot) is treated as a configuration
 property. If it matches an existing configuration property, the environment variable's
@@ -233,6 +237,8 @@ expect your ``Config\App`` to magically have that property and value at run time
 When you have the property ``$default = ['encrypt' => false]`` in your
 ``Config\Database``, you cannot change the ``encrypt`` value to an array even if
 you put ``database.default.encrypt.ssl_verify = true`` in your **.env**.
+If you want to do like that, see
+:ref:`Database Configuration <database-config-with-env-file>`.
 
 Treating Environment Variables as Arrays
 ========================================