Restriction of complete package

It would be useful to restrict a complete package (even recursively) and just whitelist / mark the public API of a code base as usable. Is there a way to do this with the checker or better use the module system available since Java 9?

Currently it's possible to annotate a package with `@Restricted` but no restriction is applied then. That's very confusing.

Therefore I suggest to either
a) implement restriction on packages (if possible)
b) apply a `@Target` annotation on [Restricted](https://github.com/kohsuke/access-modifier/blob/access-modifier-1.16/access-modifier-annotation/src/main/java/org/kohsuke/accmod/Restricted.java#L46) to prevent its use on packages