Update XR Input Source sample tutorial (#89)
Update XR Input Source sample tutorial (#89)

* update XR Input Source sample tutorial

* Update webxr-ray-input.md

* Update webxr-ray-input.md

Co-authored-by: Will Eastcott <37d41699bdee4fcb969ca499eb0f8b82c60d59cc@playcanvas.com>
playcanvas/developer.playcanvas.com,playcanvas/developer.playcanvas.com