api(isValidCoordinate): update returns description

src/core/coordinates/validCoordinate.js

@@ -7,7 +7,7 @@ const { valid3DCoordinate } = require('./valid3DCoordinate')
  * @memberof Core.Coordinates
  * @see https://github.com/M-Scott-Lassiter/jest-geojson/issues/4
  * @param {GeoJSON2DCoordinate|GeoJSON3DCoordinate} coordinate A WGS-84 array of [longitude, latitude] or [longitude, latitude, alititude]
- * @returns {boolean} True if a valid 3D GeoJSON coordinate. If invalid, it will throw an error.
+ * @returns {boolean} True if a valid 2D or 3D GeoJSON coordinate. If invalid, it will throw an error.
  * @throws {Error} Input must be an array of only two or three elments
  */
 function validCoordinate(coordinate) {