message: add link to faq from readme
diff: 9. [Troubleshooting][troubleshooting]
  +10. [FAQ][faq]
  +
  <!-- LINKS -->
  [introduction]: https://github.com/Azure/autorest/blob/master/docs/introduction.md
  [install]: https://github.com/Azure/autorest/blob/master/docs/install/readme.md
  [dev]: https://github.com/Azure/autorest/blob/master/docs/developer/readme.md
  [powershell]: https://github.com/Azure/autorest/blob/master/docs/powershell/readme.md
  [troubleshooting]: https://github.com/Azure/autorest/blob/master/docs/troubleshooting.md
  +[faq]: https://github.com/Azure/autorest/blob/master/docs/faq.md
  \ No newline at end of file
  