Remove references to _.

sumBy.js

@@ -1,12 +1,11 @@
 import baseSum from './_baseSum.js';
 
 /**
- * This method is like `_.sum` except that it accepts `iteratee` which is
+ * This method is like `sum` except that it accepts `iteratee` which is
  * invoked for each element in `array` to generate the value to be summed.
  * The iteratee is invoked with one argument: (value).
  *
  * @static
- * @memberOf _
  * @since 4.0.0
  * @category Math
  * @param {Array} array The array to iterate over.
@@ -16,7 +15,7 @@ import baseSum from './_baseSum.js';
  *
  * var objects = [{ 'n': 4 }, { 'n': 2 }, { 'n': 8 }, { 'n': 6 }];
  *
- * _.sumBy(objects, function(o) { return o.n; });
+ * sumBy(objects, function(o) { return o.n; });
  * // => 20
  */
 function sumBy(array, iteratee) {