Docs: add animated WebP example #2648

lib/output.js

@@ -383,6 +383,12 @@ function png (options) {
  *   .webp({ lossless: true })
  *   .toBuffer();
  *
+ * @example
+ * // Optimise the file size of an animated WebP
+ * const outputWebp = await sharp(inputWebp, { animated: true })
+ *   .webp({ reductionEffort: 6 })
+ *   .toBuffer();
+ *
  * @param {Object} [options] - output options
  * @param {number} [options.quality=80] - quality, integer 1-100
  * @param {number} [options.alphaQuality=100] - quality of alpha layer, integer 0-100