add starter kit

packages/tiptap-starter-kit/index.ts

@@ -0,0 +1,13 @@
+import Document from '@tiptap/document-extension'
+import History from '@tiptap/history-extension'
+import Paragraph from '@tiptap/paragraph-extension'
+import Text from '@tiptap/text-extension'
+
+export default function extensions() {
+  return [
+    new Document(),
+    new History(),
+    new Paragraph(),
+    new Text(),
+  ]
+}