Docs(Plugins): Added Leaflet.greatCircle plugin (#6403)
Docs(Plugins): Added Leaflet.greatCircle plugin (#6403)

To Overlay display > Markers & renderers section

* Update plugins.md

* Update plugins.md

* add demo for greatCircle class

stefanocudini/Leaflet,CapeSepias/Leaflet,CapeSepias/Leaflet,stefanocudini/Leaflet,Leaflet/Leaflet,CapeSepias/Leaflet,Leaflet/Leaflet,stefanocudini/Leaflet,Leaflet/Leaflet