Add missing 'abstract' tag in ol.format.filter classes

src/ol/format/filter/and.js

@@ -8,6 +8,7 @@ goog.require('ol.format.filter.LogicalNary');
  * Represents a logical `<And>` operator between two or more filter conditions.
  *
  * @constructor
+ * @abstract
  * @param {...ol.format.filter.Filter} conditions Conditions.
  * @extends {ol.format.filter.LogicalNary}
  * @api

src/ol/format/filter/comparison.js

@@ -10,6 +10,7 @@ goog.require('ol.format.filter.Filter');
  * Base class for WFS GetFeature property comparison filters.
  *
  * @constructor
+ * @abstract
  * @param {!string} tagName The XML tag name for this filter.
  * @param {!string} propertyName Name of the context property to compare.
  * @extends {ol.format.filter.Filter}

src/ol/format/filter/comparisonbinary.js

@@ -10,6 +10,7 @@ goog.require('ol.format.filter.Comparison');
  * Base class for WFS GetFeature property binary comparison filters.
  *
  * @constructor
+ * @abstract
  * @param {!string} tagName The XML tag name for this filter.
  * @param {!string} propertyName Name of the context property to compare.
  * @param {!(string|number)} expression The value to compare.

src/ol/format/filter/filter.js

@@ -7,6 +7,7 @@ goog.provide('ol.format.filter.Filter');
  * Base class for WFS GetFeature filters.
  *
  * @constructor
+ * @abstract
  * @param {!string} tagName The XML tag name for this filter.
  * @struct
  * @api

src/ol/format/filter/logicalnary.js

@@ -11,6 +11,7 @@ goog.require('ol.format.filter.Filter');
  * Base class for WFS GetFeature n-ary logical filters.
  *
  * @constructor
+ * @abstract
  * @param {!string} tagName The XML tag name for this filter.
  * @param {...ol.format.filter.Filter} conditions Conditions.
  * @extends {ol.format.filter.Filter}

src/ol/format/filter/spatial.js

@@ -11,6 +11,7 @@ goog.require('ol.format.filter.Filter');
  * relates to a given geometry.
  *
  * @constructor
+ * @abstract
  * @param {!string} tagName The XML tag name for this filter.
  * @param {!string} geometryName Geometry name to use.
  * @param {!ol.geom.Geometry} geometry Geometry.