chore(docs-app): ensure ToC links contain the path

Without the path the browser address changes so the hash
fragment is directly on the base url. Then on refresh the
browser navigates to an invalid page.

Closes #16608

Author: petebacondarwin

Diff for: docs/app/src/directives.js

@@ -91,13 +91,16 @@ directivesModule
 .component('tocTree', {
   template: '<ul>' +
       '<li ng-repeat="item in $ctrl.items">' +
-        '<a ng-href="#{{item.fragment}}">{{item.title}}</a>' +
+        '<a ng-href="{{ $ctrl.path }}#{{item.fragment}}">{{item.title}}</a>' +
         '<toc-tree ng-if="::item.children.length > 0" items="item.children"></toc-tree>' +
       '</li>' +
     '</ul>',
   bindings: {
     items: '<'
-  }
+  },
+  controller: ['$location', function($location) {
+    this.path = $location.path().replace(/^\/?(.+?)(\/index)?\/?$/, '$1');
+  }]
 })
 .directive('tocContainer', function() {
   return {