Set api annotation on classdesc, not constructor

src/ol/render/VectorContext.js

@@ -3,6 +3,7 @@
  */
 
 /**
+ * @classdesc
  * Context for drawing geometries.  A vector context is available on render
  * events and does not need to be constructed directly.
  * @api

src/ol/render/canvas/Immediate.js

@@ -16,16 +16,17 @@ import VectorContext from '../VectorContext.js';
 import {defaultTextAlign, defaultFillStyle, defaultLineCap, defaultLineDash, defaultLineDashOffset, defaultLineJoin, defaultLineWidth, defaultMiterLimit, defaultStrokeStyle, defaultTextBaseline, defaultFont} from '../canvas.js';
 import {create as createTransform, compose as composeTransform} from '../../transform.js';
 
+/**
+ * @classdesc
+ * A concrete subclass of {@link module:ol/render/VectorContext} that implements
+ * direct rendering of features and geometries to an HTML5 Canvas context.
+ * Instances of this class are created internally by the library and
+ * provided to application code as vectorContext member of the
+ * {@link module:ol/render/Event~RenderEvent} object associated with postcompose, precompose and
+ * render events emitted by layers and maps.
+ */
 class CanvasImmediateRenderer extends VectorContext {
   /**
-   * @classdesc
-   * A concrete subclass of {@link module:ol/render/VectorContext} that implements
-   * direct rendering of features and geometries to an HTML5 Canvas context.
-   * Instances of this class are created internally by the library and
-   * provided to application code as vectorContext member of the
-   * {@link module:ol/render/Event~RenderEvent} object associated with postcompose, precompose and
-   * render events emitted by layers and maps.
-   *
    * @param {CanvasRenderingContext2D} context Context.
    * @param {number} pixelRatio Pixel ratio.
    * @param {module:ol/extent~Extent} extent Extent.