Add 'package(set)' to the list

Author: amartini51

TSPL.docc/LanguageGuide/AccessControl.md

@@ -807,14 +807,15 @@ the constant, variable, property, or subscript they belong to.
 You can give a setter a *lower* access level than its corresponding getter,
 to restrict the read-write scope of that variable, property, or subscript.
 You assign a lower access level by writing
-`fileprivate(set)`, `private(set)`, or `internal(set)`
+`fileprivate(set)`, `private(set)`, `internal(set)`, or `package(set)`
 before the `var` or `subscript` introducer.
 
 > Note: This rule applies to stored properties as well as computed properties.
 > Even though you don't write an explicit getter and setter for a stored property,
 > Swift still synthesizes an implicit getter and setter for you
 > to provide access to the stored property's backing storage.
-> Use `fileprivate(set)`, `private(set)`, and `internal(set)` to change the access level
+> Use `fileprivate(set)`, `private(set)`, `internal(set)`, and `package(set)`
+> to change the access level
 > of this synthesized setter in exactly the same way as for an explicit setter
 > in a computed property.