fix delete line

Sendy_Spec.md

@@ -55,7 +55,7 @@ has_many :subscriptions, class: 'KdanPackSubscription'
 ### KdanPackSubscription
 * only apply to following packs
   * Creativity 365
-  * ---Creativity 365 Teacher & Student---
+  * ~~Creativity 365 Teacher & Student~~
   * Document 365
   * ~~Creativity 365 Education~~
   * ~~Creativity 365 Business~~