improved doc for cluster feature

Signed-off-by: Tim Deubler <tim.deubler@here.com>

Author: TerminalTim

packages/core/src/features/ClusterFeature.ts

@@ -61,6 +61,15 @@ export class ClusterFeature extends Feature<'Point'> {
      */
     properties: ClusterFeatureProperties;
 
+    /**
+     * The geometry of a cluster feature is of type 'Point',
+     * where the `coordinates` represent the geographical coordinates [longitude, latitude] of the cluster center.
+     */
+    geometry: {
+        type: 'Point',
+        coordinates: GeoJSONCoordinate
+    };
+
     /**
      * Returns the features within the cluster.
      * @returns An array containing the features within the cluster.