jq and bookmarks

0 - actual run for me

This should work, but doesn't:
```
@  $ jq '.. |= .title? as $title | .children |= map(. + {"parent": $title})' e.json
jq: error (at e.json:26): Cannot iterate over null (null)
```

This works (almost)
```
@  $ jq '. |= .title? as $title | .children |= map(. + {"parent": $title})' e.json
{
  "title": "Bookmarks bar",
  "children": [
    {
      "title": "0 indexed",
      "children": [
        {
          "title": "bookmark the first",
          "uri": "https://bookmark.the.first.com/in-0-indexed"
        },
        {
          "title": "second bookmark",
          "uri": "https://second.bookmark.com/in-0-indexed"
        }
      ],
      "parent": "Bookmarks bar"
    },
    {
      "title": "third bookmark",
      "uri": "https://third.bookmark.com/not-nested",
      "parent": "Bookmarks bar"
    },
    {
      "title": "fourth bookmark",
      "uri": "https://fourth.bookmark.com/not-nested",
      "parent": "Bookmarks bar"
    }
  ]
}
```

e.json

{
  "title": "Bookmarks bar",
  "children": [
    {
      "title": "0 indexed",
      "children": [
        {
          "title": "bookmark the first",
          "uri": "https://bookmark.the.first.com/in-0-indexed"
        }
      ]
    },
    {
      "title": "second bookmark",
      "uri": "https://second.bookmark.com/not-nested"
    }
  ]
}

f.wanted output

something like:
Bookmarks bar:
Bookmarks bar.0 indexed:
Bookmarks bar.0 indexed.Bookmarks bar.0 indexed: https://bookmark.the.first.com/in-0-indexed
Bookmarks bar.0 indexed.second bookmark: https://second.bookmark.com/not-nested