Remove commented-out info about 'exported'.

This content was hidden in 2014 and 'exported' doesn't fit with the
current model for visibility, so it's unlikely to come back.

ReferenceManual/Attributes.rst

@@ -216,18 +216,6 @@ the ``noreturn`` attribute to a function or method *type*.
         is implicitly applied to that protocol; there's no need to mark the protocol with
         the ``class_protocol`` attribute explicitly.
 
-.. Note: At the design meeting on June 17th,
-    it was decided that we don't want people to be using "exported" at the moment.
-    It's really only intended for framework development (it's used in the Obj-C overlay).
-    Commenting this out until this attribute is ready for prime time,
-    to fix <rdar://problem/17346713> Remove the "exported" attribute from the Reference
-
-    ``exported``
-        Apply this attribute to an import declaration to export
-        the imported module, submodule, or declaration from the current module.
-        If another module imports the current module, that other module can access
-        the items exported by the current module.
-
 ``objc``
     Apply this attribute to any declaration that can be represented in Objective-C---
     for example, non-nested classes, protocols,