add rdfa for breadcrumbs

src/breadcrumb-nav.ts

@@ -41,16 +41,19 @@ export function breadcrumb_nav_ext(renderer: marked.Renderer, opts: MarkdownOpti
 		},
 		renderer(token: BreadcrumbNavToken) {
 			return `<nav aria-label="breadcrumbs" ${token.attrs.html_attrs.join(' ')}>\n`
-				+ `\t<ol>\n`
+				+ `\t<ol vocab="https://schema.org/" typeof="BreadcrumbList">\n`
 				+ '\t\t'
 					+ token.items.map((tokens, index) =>{ 
-						let item = '<li>';
+						let item = '<li property="itemListElement" typeof="ListItem">\n';
 
 						if (index) {
-							item += '<span class="separator" aria-hidden="true">/</span> ';
+							item += '\t\t\t<span class="separator" aria-hidden="true">/</span>\n';
 						}
 
-						return item + this.parser.parseInline(tokens, renderer) + '</li>';
+						item += `\t\t\t<span property="name">${this.parser.parseInline(tokens, renderer)}</span>\n`;
+						item += `\t\t\t<meta property="position" content="${index + 1}">\n`;
+
+						return item +  + '\t\t</li>';
 					}).join('\n\t\t')
 				+ '\n'
 				+ `\t</ol>\n`