Setting to restrict available sections when using 'Link to an Entry' within Redactor field

[lewisjenkins]

Feature request

The mock-up below probably says it all, but it would be useful to be able to hide some (or all) sections from the 'Link to an Entry' modal when the 'Link' button is being used in Redactor. So, entire sections can then be completely hidden from the modal. And if no sections are checked in the Redactor settings below then 'Link to an Entry' should become completely unavailable as a dropdown option within the 'Link' button. This would help avoid confusion for user groups with restricted permissions who have no access (or knowledge of) other sections (this actually happened today).