Update doc examples to ES2015.

find.js

@@ -14,13 +14,13 @@ import findIndex from './findIndex.js';
  * @returns {*} Returns the matched element, else `undefined`.
  * @example
  *
- * var users = [
+ * const users = [
  *   { 'user': 'barney',  'age': 36, 'active': true },
  *   { 'user': 'fred',    'age': 40, 'active': false },
  *   { 'user': 'pebbles', 'age': 1,  'active': true }
  * ];
  *
- * find(users, function(o) { return o.age < 40; });
+ * find(users, o => o.age < 40);
  * // => object for 'barney'
  */
 const find = createFind(findIndex);