fix(docs): Add $locationProvider methods to the docs example provider

- $locationProvider.html5Mode
- $locationProvider.hashPrefix

Docs example is basically a different application on the same page, but we don't want to instantiate multiple instances of $browser or $location service, so we are overriding these providers to return the instances from parent app.

Overriding the service with $provide.value caused a provider to be auto-generated without the necessary hashPrefix and html5Mode apis.

docs/src/templates/doc_widgets.js

@@ -85,7 +85,12 @@ angular.module('ngdocs.directives', [], function($compileProvider) {
           var modules = [
             function($provide) {
               $provide.value('$browser', $browser);
-              $provide.value('$location', $location);
+              $provide.service('$location', function() {
+                this.$get = function() {
+                  return $location;
+                };
+                this.hashPrefix = this.html5Mode = angular.noop;
+              });
               $provide.decorator('$defer', function($rootScope, $delegate) {
                 return angular.extend(function(fn, delay) {
                   if (delay && delay > 500) {