title: Extending VS Code syntax highlighting
body: <p>Is there a way to extend Visual Studio Code syntax highlighting for specific items using the user settings (or similar methods not involving writing an extension)?</p>
  
  <p>I am using a color theme but would like to change the syntax colouring for a specific namespace of HTML tags, e.g.</p>
  
  <p><code>&lt;div&gt;&lt;/div&gt;</code> uses standard colouring from theme</p>
  
  <p><code>&lt;ext:div&gt;&lt;/ext:div&gt;</code> uses a different color</p>