Added missing character.

Thanks to xet7 !

client/components/cards/attachments.js

@@ -12,7 +12,7 @@ let openAttachmentId = null;
 
 
 // Stores link to the attachment for which attachment actions popup was opened
-attachmentActionsLink = null
+attachmentActionsLink = null;
 
 Template.attachmentGallery.events({
   'click .open-preview'(event) {