title: New pull request when one is already opened
body: <p>I've created pull request to project from my fork branch. Repo owner will accept it after code review but it can wait a while because he is currently busy. I didn't want to wait and on brand new branch in my fork I implemented next features. </p>
  
  <p>If now I create new pull request will it merge with previous and create one huge pull request? Or there will be two separate PR? I'm worried it will merge because in commits field on GH I see commits from previous PR.</p>