Entry link type: only show sections that have an URL

[FrDH]

Most of the time, we select the "all sections" option when enabling linking to an entry, basically so all sections created in the future will automatically be available. Unfortunately, this also enables the user to select an entry that can not be visited / has no URL.

As this plugin is all about creating links, would it not make sense to only show sections that actually have an URL?

Thanks.

[ben-callaway]

Thanks @FrDH This is similar to #105, currently investigating.