fix: 🐛 list item can have other block as first children (#1300)

✅ Closes: #1276

Author: Saul-Mirone

Diff for: packages/preset-commonmark/src/node/list-item.ts

@@ -18,7 +18,7 @@ withMeta(listItemAttr, {
 /// Schema for list item node.
 export const listItemSchema = $nodeSchema('list_item', ctx => ({
   group: 'listItem',
-  content: 'paragraph block*',
+  content: 'block+',
   attrs: {
     label: {
       default: '•',