feat(v2): docs versioning ❄️🔥 (#1983)

* wip: versioning

* wip again

* nits lint

* refactor metadata code so that we can have inobject properties optimization, fix typing

* remove buggy permalink code

* modify versioned docs fixture such that foo/baz only exists in v1.0.0

* refactor metadata.ts so that there is less transformon object

* more refactoring

* reduce test fixtures, refactoring

* refactoring readability

* finish metadata part

* refactor with readdir

* first pass of implementation

* fix mdx laoder

* split generated routes by version for performance & smaller bundle

* test data for demo

* refactor with set

* more tests

* typo

* fix typo

* better temporary ui

* stronger typing & docsVersion command

* add 100% test coverage for docsVersion command

* more test and delete manual docs cut

* cut 2.0.0-alpha.35 docs

* cut alpha.36 instead

* copyright

* delete versioned docs

* stronger test on metadata

* update typo

packages/docusaurus-plugin-content-docs/src/order.ts

@@ -5,13 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {
-  Sidebar,
-  SidebarItem,
-  SidebarItemDoc,
-  SidebarItemCategory,
-  Order,
-} from './types';
+import {Sidebar, SidebarItem, Order} from './types';
 
 // Build the docs meta such as next, previous, category and sidebar.
 export default function createOrder(allSidebars: Sidebar = {}): Order {
@@ -26,7 +20,7 @@ export default function createOrder(allSidebars: Sidebar = {}): Order {
         switch (item.type) {
           case 'category':
             indexItems({
-              items: (item as SidebarItemCategory).items,
+              items: item.items,
             });
             break;
           case 'ref':
@@ -34,12 +28,8 @@ export default function createOrder(allSidebars: Sidebar = {}): Order {
             // Refs and links should not be shown in navigation.
             break;
           case 'doc':
-            ids.push((item as SidebarItemDoc).id);
+            ids.push(item.id);
             break;
-          default:
-            throw new Error(
-              `Unknown item type: ${item.type}. Item: ${JSON.stringify(item)}`,
-            );
         }
       });
     };