fix(docs): add aria-label to Expressive Code copy-to-clipboard buttons

[Copilot]

Expressive Code renders copy buttons with title="Copy to clipboard" but no aria-label, leaving them without an accessible name for screen readers (WCAG 2.1 SC 4.1.2).

Changes

• docs/src/scripts/copy-button-aria.ts — new script that selects .expressive-code button[title]:not([aria-label]) and mirrors title → aria-label; re-runs on astro:page-load for client-side navigation
• docs/src/components/CustomHead.astro — imports the new script alongside the existing search-aria.ts and responsive-tables.ts enhancements

Follows the established pattern for DOM-based accessibility patches in this project. Only sets aria-label on buttons that don't already have one — no visual change.

[Copilot]

Pull request overview

Adds an accessibility patch so Expressive Code’s copy-to-clipboard buttons receive an accessible name by mirroring their existing title attribute into aria-label when missing, including on Astro client-side navigation.

Changes:

• Add a new DOM enhancement script to set aria-label on .expressive-code buttons based on title.
• Load the new script from CustomHead.astro alongside existing accessibility/enhancement scripts.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
docs/src/scripts/copy-button-aria.ts	New client-side enhancement that mirrors title → aria-label for copy buttons and re-applies on astro:page-load.
docs/src/components/CustomHead.astro	Imports the new script so it runs site-wide.

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[Copilot]

This new script is indented with tabs (e.g. in the querySelectorAll / forEach block). The other docs enhancement scripts use 2-space indentation (see docs/src/scripts/responsive-tables.ts and search-aria.ts), and the repo’s Prettier config is set for 2-space formatting. Reformat this file to match the established style (run Prettier or convert tabs to spaces) to avoid inconsistent diffs and formatter churn.

Suggested change

	const buttons = document.querySelectorAll<HTMLButtonElement>(
	'.expressive-code button[title]:not([aria-label])',
	);
	buttons.forEach((button) => {
	const label = button.getAttribute('title');
	if (label) {
	button.setAttribute('aria-label', label);
	}
	});
	}
	// Run on initial page load
	if (document.readyState === 'loading') {
	document.addEventListener('DOMContentLoaded', enhanceCopyButtons);
	} else {
	enhanceCopyButtons();
	const buttons = document.querySelectorAll<HTMLButtonElement>(
	'.expressive-code button[title]:not([aria-label])',
	);
	buttons.forEach((button) => {
	const label = button.getAttribute('title');
	if (label) {
	button.setAttribute('aria-label', label);
	}
	});
	}
	// Run on initial page load
	if (document.readyState === 'loading') {
	document.addEventListener('DOMContentLoaded', enhanceCopyButtons);
	} else {
	enhanceCopyButtons();