Fix tests

Author: wooorm

lib/state.js

@@ -168,6 +168,7 @@
  *   Wrap `nodes` with line endings between each node, adds initial/final line endings when `loose`.
  */
 
+import structuredClone from '@ungap/structured-clone'
 import {visit} from 'unist-util-visit'
 import {position} from 'unist-util-position'
 import {handlers as defaultHandlers} from './handlers/index.js'