docs: change Navigation from type to interface (#42281)

Navigation type should be interface so it can be documented on aio site.

fixes #37384

PR Close #42281

goldens/public-api/router/router.d.ts

@@ -169,15 +169,15 @@ export declare type LoadChildren = LoadChildrenCallback | DeprecatedLoadChildren
 
 export declare type LoadChildrenCallback = () => Type<any> | NgModuleFactory<any> | Observable<Type<any>> | Promise<NgModuleFactory<any> | Type<any> | any>;
 
-export declare type Navigation = {
+export declare interface Navigation {
+    extractedUrl: UrlTree;
+    extras: NavigationExtras;
+    finalUrl?: UrlTree;
     id: number;
     initialUrl: string | UrlTree;
-    extractedUrl: UrlTree;
-    finalUrl?: UrlTree;
-    trigger: 'imperative' | 'popstate' | 'hashchange';
-    extras: NavigationExtras;
     previousNavigation: Navigation | null;
-};
+    trigger: 'imperative' | 'popstate' | 'hashchange';
+}
 
 export declare interface NavigationBehaviorOptions {
     replaceUrl?: boolean;

packages/router/src/router.ts

@@ -260,7 +260,7 @@ export type RestoredState = {
  *
  * @publicApi
  */
-export type Navigation = {
+export interface Navigation {
   /**
    * The unique identifier of the current navigation.
    */
@@ -299,7 +299,7 @@ export type Navigation = {
    * for its own `previousNavigation`.
    */
   previousNavigation: Navigation|null;
-};
+}
 
 export type NavigationTransition = {
   id: number,