Add 2.1.3 to iframe focusable rule (#2229)

* Editorial update iframe focusable

* Add 2.1.3

Author: WilcoFiers

_rules/iframe-with-interactive-content-in-tab-order-akn7bn.md

@@ -4,13 +4,18 @@ name: Iframe with interactive elements is not excluded from tab-order
 rules_format: 1.1
 rule_type: atomic
 description: |
-  This rule checks that `iframe` elements which contain an interactive (tabbable) element are not excluded from sequential focus navigation.
+  This rule checks that `iframe` elements which contain keyboard focusable elements are not excluded from sequential focus navigation.
 accessibility_requirements:
   wcag20:2.1.1: # Keyboard (A)
     forConformance: true
     failed: not satisfied
     passed: further testing needed
     inapplicable: further testing needed
+  wcag20:2.1.3: # Keyboard (No exceptions) (AAA)
+    forConformance: true
+    failed: not satisfied
+    passed: further testing needed
+    inapplicable: further testing needed
   wcag-technique:G202: # Ensuring keyboard control for all functionality
     forConformance: false
     failed: not satisfied