feat(freesewing.dev): ToC and layout changes

packages/freesewing.shared/mdx/mdx-plugin-toc.mjs

@@ -0,0 +1,30 @@
+import {toc} from 'mdast-util-toc'
+
+const headings = {
+  en: 'Table of contents',
+  fr: 'Table des matières',
+  nl: 'Inhoudsopgave',
+  es: 'Tabla de contenido',
+  de: 'Inhaltsverzeichnis'
+}
+
+export default function mdxToc(options = {}) {
+  return (node) => {
+    const result = toc(node, { heading: false })
+
+    if (result.map) node.children = [
+      {
+        type: 'heading',
+        depth: 4,
+        children: [{
+          type: 'text',
+          value: headings[options.language || 'en']
+        }]
+      },
+      result.map
+    ]
+    else node.children = []
+
+    return
+  }
+}