Whenever we append new item for the link.
We will need to override the core quickAddForm & quickEditForm.
Just to append the new item into it ( 1 line of code ) .
Will be nice, if there's allowedTypes in .xml so that we could pass which link Item to be shown instead of overriding the core.
This will also control the form to not have link item that will be not used for the context.
For example, table of content widget which has following link item "email", "url", "sitetreelink", "resource". The email item will not be used for the listing. Thus if there's allowedTypes, we can remove "email" from getting rendered in the form.