feat: add Emmet pro tip to FAQ accordion lesson

Explain details*3>summary+p shorthand for quickly scaffolding
multiple disclosure widgets with nested summary and p elements.

lessons/23-html-details-summary.json

@@ -62,7 +62,7 @@
 		{
 			"id": "faq-accordion",
 			"title": "FAQ Accordion",
-			"description": "Multiple <kbd>&lt;details&gt;</kbd> elements create an accordion-style FAQ. Each question can be expanded independently.<br><br>This is a common pattern for FAQ pages, documentation, and help sections.",
+			"description": "Multiple <kbd>&lt;details&gt;</kbd> elements create an accordion-style FAQ. Each question can be expanded independently.<br><br><b>Pro tip:</b> Type <kbd>details*3&gt;summary+p</kbd> and press Tab for Emmet expansion. <kbd>*3</kbd> creates 3 elements, <kbd>&gt;</kbd> nests inside, <kbd>+</kbd> adds siblings.",
 			"task": "Create an FAQ section with:<br>1. An <kbd>&lt;h1&gt;</kbd> saying 'Frequently Asked Questions'<br>2. Three <kbd>&lt;details&gt;</kbd> elements, each with a question in <kbd>&lt;summary&gt;</kbd> and an answer in <kbd>&lt;p&gt;</kbd>",
 			"previewHTML": "",
 			"previewBaseCSS": "body { font-family: system-ui; min-height: 100vh; background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%); display: flex; flex-direction: column; justify-content: center; padding: 40px; margin: 0; box-sizing: border-box; } h1 { font-size: 2.5rem; color: #4a4a4a; text-align: center; margin: 0 0 30px 0; } details { background: white; border-radius: 12px; margin-bottom: 15px; padding: 20px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); } summary { font-size: 1.3rem; font-weight: 600; color: #5c5c5c; cursor: pointer; list-style: none; } summary::before { content: '▸ '; color: #fcb69f; } details[open] summary::before { content: '▾ '; } details p { margin: 15px 0 0 0; color: #666; line-height: 1.6; }",