Add aria-level as a required prop for the heading role

Author: jessebeach

scripts/roles.json

@@ -3175,7 +3175,9 @@
     ],
     "requiredContextRole": [],
     "requiredOwnedElements": [],
-    "requiredProps": [],
+    "requiredProps": [
+      ["aria-level", 2]
+    ],
     "superClass": ["sectionhead"]
   },
   "img": {

src/etc/roles/literal/headingRole.js

@@ -53,7 +53,9 @@ const headingRole: ARIARoleDefinition = {
   requireContextRole: [],
   requiredContextRole: [],
   requiredOwnedElements: [],
-  requiredProps: {},
+  requiredProps: {
+    'aria-level': 2,
+  },
   superClass: [
     [
       'roletype',