Got callouts about working, simplified markdown setup

resources/js/editor/markdown-serializer.js

@@ -0,0 +1,15 @@
+import {MarkdownSerializer, defaultMarkdownSerializer} from "prosemirror-markdown";
+import {docToHtml} from "./util";
+
+const nodes = defaultMarkdownSerializer.nodes;
+const marks = defaultMarkdownSerializer.marks;
+
+nodes.callout = function(state, node) {
+    const html = docToHtml({ content: [node] });
+    state.write(html);
+    state.closeBlock();
+};
+
+const serializer = new MarkdownSerializer(nodes, marks);
+
+export default serializer;