Re-add the GamePad docs for 3.1.0
Re-add the GamePad docs for 3.1.0

flabbyfabby/flixel-docs,Gama11/flixel-docs,flabbyfabby/flixel-docs,Doppp/flixel-docs,Gama11/flixel-docs,jcward/flixel-docs,jcward/flixel-docs,Doppp/flixel-docs,flabbyfabby/flixel-docs