版本：
文件：
- https://cdn.bootcdn.net/ajax/libs/leaflet.fullscreen/4.0.0/Control.FullScreen.css
- https://cdn.bootcdn.net/ajax/libs/leaflet.fullscreen/4.0.0/Control.FullScreen.js
- https://cdn.bootcdn.net/ajax/libs/leaflet.fullscreen/4.0.0/Control.FullScreen.min.css
- https://cdn.bootcdn.net/ajax/libs/leaflet.fullscreen/4.0.0/Control.FullScreen.min.js
- https://cdn.bootcdn.net/ajax/libs/leaflet.fullscreen/4.0.0/icon-fullscreen.svg