title: How to bold title html tag
body: <p>I see a interesting thing with title tag html, the title tag can bold. Like this page. Anyone know how to do it?
  <a href="https://i.stack.imgur.com/lUjoq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lUjoq.png" alt="bold title tag"></a></p>