docs: add note for In-Model Validation

Author: kenjis

user_guide_src/source/helpers/form_helper.rst

@@ -536,6 +536,10 @@ The following functions are available:
     The returned array is the same as ``Validation::getErrors()``.
     See :ref:`Validation <validation-redirect-and-validation-errors>` for details.
 
+    .. note:: This function does not work with :ref:`in-model-validation`. If you
+        want to get the validation errors in model validation, see
+        :ref:`model-getting-validation-errors`.
+
     Example::
 
         <?php $errors = validation_errors(); ?>
@@ -555,6 +559,10 @@ The following functions are available:
 
     This function uses :php:func:`validation_errors()` internally.
 
+    .. note:: This function does not work with :ref:`in-model-validation`. If you
+        want to get the validation errors in model validation, see
+        :ref:`model-getting-validation-errors`.
+
     Example::
 
         <?= validation_list_errors() ?>
@@ -575,6 +583,10 @@ The following functions are available:
 
     This function uses :php:func:`validation_errors()` internally.
 
+    .. note:: This function does not work with :ref:`in-model-validation`. If you
+        want to get the validation errors in model validation, see
+        :ref:`model-getting-validation-errors`.
+
     Example::
 
         <?= validation_show_error('username') ?>

user_guide_src/source/models/model.rst

@@ -456,6 +456,8 @@ Cleans out the database table by permanently removing all rows that have 'delete
 
 .. literalinclude:: model/026.php
 
+.. _in-model-validation:
+
 In-Model Validation
 ===================
 
@@ -542,6 +544,8 @@ Getting Validation Result
 Now, whenever you call the ``insert()``, ``update()``, or ``save()`` methods, the data will be validated. If it fails,
 the model will return boolean **false**.
 
+.. _model-getting-validation-errors:
+
 Getting Validation Errors
 -------------------------