docs: add sample code for array validation rules

tests/system/Validation/ValidationTest.php

@@ -440,6 +440,7 @@ public function testRulesSetup($rules, $expected, array $errors = [])
         $data = ['foo' => ''];
         $this->validation->setRules(['foo' => $rules], $errors);
         $this->validation->run($data);
+
         $this->assertSame($expected, $this->validation->getError('foo'));
     }
 
@@ -468,13 +469,24 @@ public function rulesSetupProvider(): Generator
                 ['rules' => 'min_length[10]'],
                 'The foo field must be at least 10 characters in length.',
             ],
+            [
+                ['rules' => ['min_length[10]']],
+                'The foo field must be at least 10 characters in length.',
+            ],
             [
                 [
                     'label' => 'Foo Bar',
                     'rules' => 'min_length[10]',
                 ],
                 'The Foo Bar field must be at least 10 characters in length.',
             ],
+            [
+                [
+                    'label' => 'Foo Bar',
+                    'rules' => ['min_length[10]'],
+                ],
+                'The Foo Bar field must be at least 10 characters in length.',
+            ],
             [
                 [
                     'label' => 'Foo Bar',

user_guide_src/source/libraries/validation/006.php

@@ -4,3 +4,8 @@
     'username' => 'required',
     'password' => 'required|min_length[10]',
 ]);
+// or
+$validation->setRules([
+    'username' => 'required',
+    'password' => ['required', 'min_length[10]'],
+]);

user_guide_src/source/libraries/validation/007.php

@@ -4,3 +4,8 @@
     'username' => ['label' => 'Username', 'rules' => 'required'],
     'password' => ['label' => 'Password', 'rules' => 'required|min_length[10]'],
 ]);
+// or
+$validation->setRules([
+    'username' => ['label' => 'Username', 'rules' => 'required'],
+    'password' => ['label' => 'Password', 'rules' => ['required', 'min_length[10]']],
+]);