Implementation of drustack/Leaflet.SyncView Pull Request #1: https://github.com/drustack/Leaflet.SyncView/pull/1
Merge branch '3254562-add-drustackleaflet.syncview-support-10.2.x' of git.drupal.org:issue/leaflet-3254562 into 3254562-add-drustackleaflet.syncview-support-10.2.x