fixes broken faq link

Author: caseyyee

README.md

@@ -39,7 +39,7 @@ This asset works by utilizing Unity's WebGL platform support and therefore share
 
 * [Setting up a Unity project for WebVR](./docs/project-setup.md)
 * [Publishing](./docs/publishing.md)
-* [Troubleshooting and FAQ](./docs/faq.md)
+* [Troubleshooting and FAQ](./docs/troubleshooting-faq.md)
 * [Controllers and input system](./docs/controllers.md)