isolated note importer

app/components/SimpleEditor/elements/isolatedNote/IsolatedNoteHTMLConverter.js

 export default {
   type: 'isolated-note',
-  tagName: 'isolated-note'
+  tagName: 'isolated-note',
+
+  import: function (el, node, converter) {
+    node.content = converter.annotatedText(el, [node.id, 'content'])
+  }
 }