Merge pull request #6328 from quentin-ol/master

ol.geom.polygon documentation update on the coordinates format

src/ol/geom/polygon.js

@@ -26,7 +26,12 @@ goog.require('ol.math');
  *
  * @constructor
  * @extends {ol.geom.SimpleGeometry}
- * @param {Array.<Array.<ol.Coordinate>>} coordinates Coordinates.
+ * @param {Array.<Array.<ol.Coordinate>>} coordinates Array of linear
+ *     rings that define the polygon. The first linear ring of the array
+ *     defines the outer-boundary or surface of the polygon. Each subsequent
+ *     linear ring defines a hole in the surface of the polygon. A linear ring
+ *     is an array of vertices' coordinates where the first coordinate and the
+ *     last are equivalent.
  * @param {ol.geom.GeometryLayout=} opt_layout Layout.
  * @api stable
  */