Add related function for each module. [closes #2932]

keyBy.js

@@ -12,6 +12,7 @@ import reduce from './reduce.js';
  * @param {Array|Object} collection The collection to iterate over.
  * @param {Function} iteratee The iteratee to transform keys.
  * @returns {Object} Returns the composed aggregate object.
+ * @see groupBy, partition
  * @example
  *
  * const array = [