fix(AgmPolyline): fix doubleclick output

Closes #1041

Author: doom777

src/core/directives/polyline.ts

@@ -198,7 +198,7 @@ export class AgmPolyline implements OnDestroy, OnChanges, AfterContentInit {
   private _addEventListeners() {
     const handlers = [
       {name: 'click', handler: (ev: PolyMouseEvent) => this.lineClick.emit(ev)},
-      {name: 'dbclick', handler: (ev: PolyMouseEvent) => this.lineDblClick.emit(ev)},
+      {name: 'dblclick', handler: (ev: PolyMouseEvent) => this.lineDblClick.emit(ev)},
       {name: 'drag', handler: (ev: MouseEvent) => this.lineDrag.emit(ev)},
       {name: 'dragend', handler: (ev: MouseEvent) => this.lineDragEnd.emit(ev)},
       {name: 'dragstart', handler: (ev: MouseEvent) => this.lineDragStart.emit(ev)},