update link (#877)

Author: mongoKart

source/index.txt

@@ -119,7 +119,7 @@ Featured Community-Supported Libraries
 
    .. card::
       :cta: Mongoose
-      :url: https://mongoosejs.com/docs/guide.html
+      :url: https://mongoosejs.com/docs/index.html
       :icon: /figures/icons/mongoose.svg
       :icon-alt: Mongoose icon