fix(#22): drop details/option/datalist from focusable set (Copilot review)

Per HTML §6.6.3 'Sequential focus navigation', none of <details>,
<option>, or <datalist> are focusable by default:
- <details>: the focusable control is its <summary> child
- <option>: not in default tab order; <select> is focused and arrow keys
  navigate options within it
- <datalist>: no user-facing UI; the paired <input list> is focused

Including them in UNCONDITIONAL_FOCUSABLE_TAGS was over-aggressive and
caused false positives on this rule. Tests updated to pin the
now-allowed cases.

Author: johanrd

lib/rules/template-no-role-presentation-on-focusable.js

@@ -59,16 +59,19 @@ function hasPresentationRole(node) {
 // focusable by default — clicks on a label forward to its associated control,
 // but the label itself isn't in the tab order. So it's excluded here even
 // though `isHtmlInteractiveContent` would return true for it.
+// Per HTML §6.6.3 "Sequential focus navigation", tags in the default tab
+// order without further qualification. Explicitly excluded:
+//   - <details>: the focusable control is its <summary> child, not details.
+//   - <option>: not in the default focus order; <select> is focused and
+//     arrow keys navigate options within it (not Tab).
+//   - <datalist>: no user-facing UI; the paired <input list> is focused.
 const UNCONDITIONAL_FOCUSABLE_TAGS = new Set([
   'button',
   'select',
   'textarea',
   'iframe',
   'embed',
   'summary',
-  'details',
-  'option',
-  'datalist',
 ]);
 
 // Form-control tags whose `disabled` attribute removes them from the tab order

tests/lib/rules/template-no-role-presentation-on-focusable.js

@@ -55,6 +55,16 @@ ruleTester.run('template-no-role-presentation-on-focusable', rule, {
     '<template><button disabled role="presentation">Click</button></template>',
     '<template><input type="text" disabled role="presentation" /></template>',
 
+    // HTML §6.6.3 sequential-focus-navigation elements that are NOT
+    // focusable themselves (focus lands on a child or a sibling):
+    //   - <details> — focusable control is its <summary>, not details itself
+    //   - <option> — not in default tab order; <select> receives focus
+    //   - <datalist> — no user-facing UI; paired <input list> is focused
+    // So role="presentation" on these is allowed.
+    '<template><details role="presentation"><summary>Hi</summary></details></template>',
+    '<template><option role="presentation">X</option></template>',
+    '<template><datalist role="presentation"><option>X</option></datalist></template>',
+
     // contenteditable falsy values — not focusable, presentation is allowed.
     '<template><div contenteditable="false" role="presentation"></div></template>',
 
@@ -161,11 +171,6 @@ ruleTester.run('template-no-role-presentation-on-focusable', rule, {
       output: null,
       errors: [{ messageId: 'invalidPresentation' }],
     },
-    {
-      code: '<template><details role="presentation"><summary>Hi</summary></details></template>',
-      output: null,
-      errors: [{ messageId: 'invalidPresentation' }],
-    },
     {
       code: '<template><summary role="none">Hi</summary></template>',
       output: null,