fix documentation and examples of feature creators (#411)
fix documentation and examples of feature creators (#411)

show the correct number of nested arrays in the polygon and multi* feature creator helper functions
Turfjs/turf,jvrousseau/turf,tilemapjp/turf,stebogit/turf,hooplert/jesper,tilemapjp/turf,jvrousseau/turf,Turfjs/turf,hooplert/jesper,ath0mas/turf,dpmcmlxxvi/turf,Turfjs/turf,stebogit/turf,dpmcmlxxvi/turf,dpmcmlxxvi/turf,hooplert/jesper,stebogit/turf,jvrousseau/turf,ath0mas/turf,tilemapjp/turf