fix: html entities encoded twice in toc plugin

closes #4908

Author: brc-dd

src/node/markdown/markdown.ts

@@ -320,6 +320,7 @@ export async function createMarkdownRenderer(
     .use(titlePlugin)
     .use(tocPlugin, {
       slugify,
+      format: (s) => s.replaceAll('&', '&'), // encoded twice because of restoreEntities
       ...options.toc
     } as TocPluginOptions)