docs(angular.bootstrap): clarify modules parameter

It was not clear what you could pass to specify modules to load in the
`module` parameter of this function. The `modules` parameter takes an
array.

The main case is to provide a String, which is the name of a "predefined"
angular module.
The side cases are to provide a Function (or an annotated function in the
form of an Array), which will be invoked by the injector as a run block.

It is not possible to "define" new modules via this parameter.

Closes #3692

Author: petebacondarwin

src/Angular.js

@@ -1017,7 +1017,9 @@ function angularInit(element, bootstrap) {
  * They must use {@link api/ng.directive:ngApp ngApp}.
  *
  * @param {Element} element DOM element which is the root of angular application.
- * @param {Array<String|Function>=} modules an array of module declarations. See: {@link angular.module modules}
+ * @param {Array<String|Function|Array>=} modules an array of modules to load into the application.
+ *     Each item in the array should be the name of a predefined module or a (DI annotated)
+ *     function that will be invoked by the injector as a run block. See: {@link angular.module modules}
  * @returns {AUTO.$injector} Returns the newly created injector for this app.
  */
 function bootstrap(element, modules) {