title: Error object inside catch is of type unknown
body: <p>I have the following code:</p>
  <pre class="lang-js prettyprint-override"><code>try {
    phpDoc(vscode.window.activeTextEditor);
  } catch (err) {
    console.error(err);
    vscode.window.showErrorMessage(err.message);
  }
  </code></pre>
  <p>however <code>err.message</code> gets the error <code>Object is of type 'unknown'.ts(2571)</code> on <code>err.</code>, but I cannot type the object in <code>catch (err: Error)</code>.</p>
  <p>What should I do?</p>