add toc demo

docs/src/demos/Guide/NodeViews/TableOfContents/TableOfContents.js

@@ -0,0 +1,27 @@
+import { Node, mergeAttributes } from '@tiptap/core'
+import { VueRenderer } from '@tiptap/vue'
+import Component from './Component.vue'
+
+export default Node.create({
+  name: 'tableOfContents',
+
+  group: 'block',
+
+  atom: true,
+
+  parseHTML() {
+    return [
+      {
+        tag: 'toc',
+      },
+    ]
+  },
+
+  renderHTML({ HTMLAttributes }) {
+    return ['toc', mergeAttributes(HTMLAttributes)]
+  },
+
+  addNodeView() {
+    return VueRenderer(Component)
+  },
+})