Fixed some jsdoc issues.

src/ol/style/Image.js

@@ -163,6 +163,7 @@ class ImageStyle {
   /**
    * Get the image pixel ratio.
    * @param {number} pixelRatio Pixel ratio.
+   * @return {number} Pixel ratio.
    */
   getPixelRatio(pixelRatio) {
     return 1;

src/ol/style/RegularShape.js

@@ -243,6 +243,7 @@ class RegularShape extends ImageStyle {
   /**
    * Get the image pixel ratio.
    * @param {number} pixelRatio Pixel ratio.
+   * @return {number} Pixel ratio.
    */
   getPixelRatio(pixelRatio) {
     return pixelRatio;