docs($interval): cancel() takes a promise not a number

Closes #6485

Author: MikeMcElroy

src/ng/interval.js

@@ -168,7 +168,7 @@ function $IntervalProvider() {
       * @description
       * Cancels a task associated with the `promise`.
       *
-      * @param {number} promise Promise returned by the `$interval` function.
+      * @param {promise} promise returned by the `$interval` function.
       * @returns {boolean} Returns `true` if the task was successfully canceled.
       */
     interval.cancel = function(promise) {

src/ngMock/angular-mocks.js

@@ -498,7 +498,7 @@ angular.mock.$IntervalProvider = function() {
      * @description
      * Cancels a task associated with the `promise`.
      *
-     * @param {number} promise A promise from calling the `$interval` function.
+     * @param {promise} promise A promise from calling the `$interval` function.
      * @returns {boolean} Returns `true` if the task was successfully cancelled.
      */
     $interval.cancel = function(promise) {