title: How to add a static unit (text) to a TextFormField in Flutter?
body: <p>I currently have this <code>TextFormField</code> with a hintText:</p>
  <p><a href="https://i.stack.imgur.com/TqaP1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TqaP1.png" alt="Current TextFormField" /></a></p>
  <p>the goal is to add Units inside the TextFormField, regardless of whether the user is typing or not. It should kinda look like this:</p>
  <p><a href="https://i.stack.imgur.com/ZRl4w.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZRl4w.png" alt="goal" /></a></p>
  <p>How to achieve this?
  Also, how to center the value?</p>
  <p>Here's my current code for the TextFormField:</p>
  <pre><code>TextFormField(
    decoration: InputDecoration(
      hintText: '0.0',
      contentPadding: EdgeInsets.symmetric(horizontal: 20.0, vertical: 5.0),
      filled: true,
      fillColor: Colors.white24,
      floatingLabelBehavior: FloatingLabelBehavior.never,
      border: OutlineInputBorder(
        borderRadius: BorderRadius.circular(10.0),
        borderSide: BorderSide.none,
      ),
      counterText: '',
    ),
  ),
  </code></pre>