fix: missing 外语学院 in sidebar

sidebars.js

@@ -108,6 +108,22 @@ const sidebars = {
             },
           ],
         },
+        {
+          type: 'category',
+          label: '外语学院',
+          link: {
+            type: 'generated-index',
+            title: '外语学院',
+            description: '外语学院的课程资料汇总',
+            slug: '/undergraduate/外语学院',
+          },
+          items: [
+            {
+              type: 'autogenerated',
+              dirName: 'undergraduate/外语学院',
+            },
+          ],
+        },
       ],
     },
     {