Update Learning-Environment-Create-New.md (#1650)

docs/Learning-Environment-Create-New.md

 positive values and one to specify negative values for each action, for a total
 of four keys.
 
-1. Select the `RollerBallPlayer` Aset to view its properties in the Inspector.
+1. Select the `RollerBallPlayer` Asset to view its properties in the Inspector.
 2. Expand the **Key Continuous Player Actions** dictionary (only visible when using
     a **PlayerBrain**).
 3. Set **Size** to 4.