title: TO DO list in rmarkdown
body: <p>There is a handy feature on github markup which can create a nice formatted <em>TO DO list</em> and it can be used as follows:</p>
  
  <pre><code>- [ ] my first item in list
  - [ ] my second item in list
    - [ ] first sub item in second item in list
  - [x] my third item in list, already done
  </code></pre>
  
  <p>Which looks like:  </p>
  
  <p><img src="https://i.stack.imgur.com/wYeox.png" alt="github todo list"></p>
  
  <p>Is there anything similar available in <code>rmarkdown</code>?</p>