title: formatOnSave doesn't work in vscode
body: <p>I installed C/C++ extensions, and added lines below to user settings:</p>
  
  <pre><code>"editor.formatOnSave": true
  "C_Cpp.clang_format_path": "C:/Progra~2/LLVM/bin/clang-format.exe"
  "C_Cpp.clang_format_fallbackStyle": "LLVM"
  "C_Cpp.clang_format_formatOnSave": true
  </code></pre>
  
  <p>but alt-shift-F, ctrl-s(save) both don't reformat codes at all.</p>
  
  <p>I tried to remove vscode completely/reinstall/reboot, but didn't work.</p>
  
  <p>And there's no workspace settings seperately.</p>
  
  <p>Is there something I missed?</p>