Docs: Fix the description of PrivateName in DETAILS.md

DETAILS.md

@@ -55,10 +55,10 @@ However, in normal usage which does not reference these runtime metaprogramming-
 
 Private state is not keyed on property keys--Strings or Symbols--but instead on Private Names. Literal references like `#x` are lexically bound to a Private Name which is textually present in the definition of a class, but decorators can create new, anonymous private fields by imperatively creating Private Names and adding them to the List of fields defined for the class.
 
-To create and use private names, a new function `PrivateName` is created:
-- `new PrivateName(description)` creates a new Private Name object, which cannot be used as a property key.
-- `PrivateName.prototype.get(object)` gets the private field or method value from the object, or invokes a getter, or throws a *ReferenceError* if it is not present.
-- `PrivateName.prototype.set(object)` sets the private field value in the object, or invokes a setter, or throws a *ReferenceError* if it is not present or if it is a private method.
+There is no direct interface for creating a PrivateName, but they are passed into decorators in as a `key`, and are objects with the following properties:
+- *privateName*.`get`(*object*) gets the private field or method value from the object, or invokes a getter, or throws a *ReferenceError* if it is not present.
+- *privateName*.`get`(*object*, *value*) sets the private field value in the object, or invokes a setter, or throws a *ReferenceError* if it is not present or if it is a private method.
+- *privateName*.`description` is a string which represents the PrivateName; for example, it would be `x` for a PrivateName which is textually `#x`.
 
 The interface for adding a private field to an object is to add a field descriptor using a decorator. A particular private name may be used just once, to define a single field. With this pattern, each private field is added by exactly one class.