Add support for writing WFS GetFeature

src/objectliterals.jsdoc

@@ -325,6 +325,24 @@
  *     when writing out the GML, this will override the default provided.
  */
 
+/**
+ * @typedef {Object} olx.format.WFSOptions
+ * @property {string} featureNS The namespace URI used for features.
+ * @property {string} featureType
+ */
+
+/**
+ * @typedef {Object} olx.format.WFSWriteGetFeatureOptions
+ * @property {string} featureNS The namespace URI used for features.
+ * @property {string} featurePrefix The prefix for the feature namespace.
+ * @property {Array.<string>} featureTypes The feature type names.
+ * @property {string|undefined} srsName SRS name. No srsName attribute will be
+ *     set on geometries when this is not provided.
+ * @property {string|undefined} handle Handle.
+ * @property {string|undefined} outputFormat Output format.
+ * @property {number} maxFeatures Maximum number of features to fetch.
+ */
+
 /**
  * @typedef {Object} olx.interaction.DoubleClickZoomOptions
  * @property {number|undefined} duration Animation duration in milliseconds. Default is `250`.