docs(404 errors): provide a better 404 experience

It is a bit rough and ready but does a better job than nothing.

docs/app/assets/Error404.html

@@ -0,0 +1,13 @@
+<h1>Welcome To AngularJS</h1>
+
+<p>The page you were looking for is not here. Perhaps you were looking for something else...</p>
+
+<div class="search-results-frame" ng-controller="Error404SearchCtrl">
+
+  <div ng-repeat="(key, value) in results" ng-show="value.length">
+    <h4>{{ key }}</h4>
+    <ul class="search-results">
+      <li ng-repeat="item in value"><a ng-href="{{ item.path }}">{{ item.name }}</a></li>
+    </ul>
+  </div>
+</div>

docs/app/src/docs.js

@@ -87,7 +87,7 @@ angular.module('DocsController', [])
         breadcrumbPath += '/';
       });
     } else {
-      $scope.currentArea = null;
+      $scope.currentArea = NG_NAVIGATION['api'];
       $scope.breadcrumb = [];
     }
   });

docs/app/src/search.js

@@ -45,6 +45,10 @@ angular.module('search', [])
   };
 }])
 
+.controller('Error404SearchCtrl', ['$scope', '$location', 'docsSearch', function($scope, $location, docsSearch) {
+  $scope.results = docsSearch($location.path().split(/[\/\.:]/).pop());
+}])
+
 .factory('lunrSearch', function() {
   return function(properties) {
     if (window.RUNNING_IN_NG_TEST_RUNNER) return null;

docs/config/templates/indexPage.template.html

@@ -219,7 +219,7 @@
         </div>
         <div class="grid-right">
           <div id="loading" ng-show="loading">Loading...</div>
-          <div ng-hide="loading" ng-include="currentPage.outputPath" onload="afterPartialLoaded()"  autoscroll></div>
+          <div ng-hide="loading" ng-include="currentPage.outputPath || 'Error404.html'" onload="afterPartialLoaded()"  autoscroll></div>
         </div>
       </div>
     </section>