title: Setting title for code line in RStudio
body: <p>I use RStudio.</p>
  
  <p>The default title of each line is "Untitled" as you can see in the first picture.
  <img src="https://i.stack.imgur.com/8AISm.png" alt="enter image description here"></p>
  
  <p>Today, I found that the title of each line can be modified. As we can see, the title in the second picture is different.
  <img src="https://i.stack.imgur.com/uL2AA.png" alt="enter image description here"></p>
  
  <p>But I don't know how to set the title. Can anyone tell me how to do it? Thank you very much!! :-)</p>