Fix docs on registering your own chart type.
Fix docs on registering your own chart type.

benpickles/peity,dbirchak/peity,FabMeg/tripping-wight,FabMeg/tripping-wight,benpickles/peity,benpickles/peity,dbirchak/peity,wallisnow/peity,dbirchak/peity,wallisnow/peity,wallisnow/peity