Update Documentation/CrossPlatform/UsingARFoundation.md
Update Documentation/CrossPlatform/UsingARFoundation.md

Co-Authored-By: CDiaz-MS <19f4ee495ae581dd14b2b7dfa92cb6fd5513c53b@users.noreply.github.com>
killerantz/HoloToolkit-Unity,killerantz/HoloToolkit-Unity,killerantz/HoloToolkit-Unity,DDReaper/MixedRealityToolkit-Unity,killerantz/HoloToolkit-Unity