title: I can not find "Documentation for Android SDK" in sdk manager
body: <p>I have one problem and it is about find the "Documentation for Android SDK".I search in google and in this site and I find the solution about this <a href="https://stackoverflow.com/questions/15748558/android-developer-documentation-download">topic</a></p>
  
  <p>but I can not find the "Documentation for Android SDK" in my sdk manager??</p>
  
  <p>thank you.</p>