title: Can't complete a Pull request on Azure DevOps
body: <p>I can't see the option to complete an already approved pull request on Azure DevOps.  The weird thing is my team member see that option when they go into my pull request.  According to the <a href="https://docs.microsoft.com/en-us/azure/devops/repos/git/pullrequest?view=azure-devops#complete-a-pull-request" rel="noreferrer">Microsoft Doc</a>, I should see the Complete option where the Abandon dropdown is.</p>
  
  <p>I don't have much luck googling the answer, does this have to do with policy or branch security, if so which option should I enabled? I'm the administrator of the repository by the way.</p>
  
  <p><a href="https://i.stack.imgur.com/gAIwp.png" rel="noreferrer"><img src="https://i.stack.imgur.com/gAIwp.png" alt="enter image description here"></a></p>