Clarify that any option keys can be used
Clarify that any option keys can be used

Fixes #4001.

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