title: How to modify a nested object with jq
body: <p>Given this</p>
  
  <pre><code>{
    "some": "property",
    "nested": {
      "hello": "world"
    }
  }
  </code></pre>
  
  <p>I'd like to get this result with jq</p>
  
  <pre><code>{
    "some": "property",
    "nested": {
      "hello": "world",
      "freshly": "added"
    }
  }
  </code></pre>
  
  <p>So how can I add the freshly added field ? I don't know how many properties are at root level (and I want to keep them all), I only know the name of the nested object (here "nested"), the name of the property I'd like to add (here "freshly") and its value.</p>