fix(DOCUMENTATION): fix incorrect example description
fix(DOCUMENTATION): fix incorrect example description

The example description for the `VRTK_ContentHandler` had been copied
and pasted from a previous script and was incorrect. The text has been
updated so it's more appropriate.
gpvigano/VRTK,mattboy64/SteamVR_Unity_Toolkit,Innoactive/IA-unity-VR-toolkit-VRTK,gpvigano/SteamVR_Unity_Toolkit,phr00t/SteamVR_Unity_Toolkit,gomez-addams/SteamVR_Unity_Toolkit,virror/VRTK,mbbmbbmm/SteamVR_Unity_Toolkit,nmccarty/htvr,bengolds/SteamVR_Unity_Toolkit,adamjweaver/VRTK,TMaloteaux/SteamVR_Unity_Toolkit,red-horizon/VRTK,thestonefox/VRTK,mimminito/SteamVR_Unity_Toolkit,Blueteak/SteamVR_Unity_Toolkit,jcrombez/SteamVR_Unity_Toolkit,thestonefox/SteamVR_Unity_Toolkit,thacio/SteamVR_Unity_Toolkit,Fulby/VRTK,pargee/SteamVR_Unity_Toolkit