fix: blog 链接用新标签显示

aio/content/navigation.json

@@ -19,6 +19,7 @@
     {
       "url": "https://blog.wangke.io/",
       "title": "译者博客",
+      "external": true,
       "tooltip": "译者汪志成的博客，包括翻译文章和原创文章"
     },
     {

aio/src/app/layout/top-menu/top-menu.component.ts

@@ -11,11 +11,12 @@ import { NavigationNode } from 'app/navigation/navigation.service';
   template: `
     <ul role="navigation">
       <li *ngFor="let node of nodes">
-        <a class="nav-link" [class.highlight]="node.highlight" [href]="node.url" [title]="node.title">
+        <a class="nav-link" [class.highlight]="node.highlight" [href]="node.url" [title]="node.tooltip || node.title"
+           [target]="node.external?'_blank':null">
           <span class="nav-link-inner">{{ node.title }}</span>
         </a>
       </li>
-    </ul>`
+    </ul>`,
 })
 export class TopMenuComponent {
   @Input() nodes: NavigationNode[];

aio/src/app/navigation/navigation.model.ts

@@ -14,6 +14,7 @@ export interface NavigationNode {
   hidden?: boolean;
   divider?: boolean;
   highlight?: boolean;
+  external?: boolean;
   children?: NavigationNode[];
 }