Remove invalid role="menu" from the navbar collapse toggler

[cwickham]

Description

Fixes #14615.

The website navbar's hamburger toggle rendered as a <button> with role="menu". That role is not valid on a button. axe-core reports it as aria-allowed-role. WAVE reports the same markup as an Error (aria_menu_broken), mapped to WCAG 2.2 SC 2.1.1 and 4.1.2, because a menu must contain at least one menuitem child. The toggle only appears when the navbar collapses at narrow viewports, so the violation only shows in mobile-width scans.

Why the role was there. #9553 (May 2024) added roles because Lighthouse reported that role="button" did not support aria-expanded. That was true under ARIA 1.1, which the axe-core of that time used. ARIA 1.2 permits aria-expanded on the button role, so the override is no longer needed. A second commit in #9553 already replaced role="menu" on the dropdown toggles with role="link". The hamburger toggler was the one instance left.

The fix. Remove the role attribute. The button keeps aria-controls, aria-expanded, and its "Toggle navigation" label. This matches the markup in Bootstrap's own navbar documentation, which carries no role. A repo-wide search found no other role="menu", and no CSS, JS, or test keys off it.

Verification. With the two-file repro from the issue at a 600 px viewport: 1 axe-core violation (aria-allowed-role on .navbar-toggler) before the fix, 0 after, with best-practice rules on. After the fix, a click still flips aria-expanded to true and opens the collapse.

New test. A website smoke-all test (tests/docs/smoke-all/website/navbar-toggler-role/) asserts that the rendered toggler carries aria-expanded, aria-controls, and aria-label but no role attribute. The fix is a static template change, so no browser test is needed. The test fails against the old markup (verified by temporarily restoring role="menu").

Checklist

I have (if applicable):

• referenced the GitHub issue this PR closes
• updated the appropriate changelog in the PR
• ensured the present test suite passes
• added new tests
• created a separate documentation PR in Quarto's website repo and linked it to this PR — not applicable: this PR changes internal navbar markup only, and no documented option or behavior changes

AI-assisted PR

• AI tool used: Claude Code
• Codebase grounding: local clone (git history of the template, repo-wide search, rendered repro)
• Human review: I have reviewed, tested, and verified the AI-generated content before submitting.

Note: autonomous AI agents submitting PRs without human oversight are not permitted — see the Code of Conduct.

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