Comment/docstring tweaks for typing.py.
diff --git a/Lib/typing.py b/Lib/typing.py
index 4bd2135..b7f3ffa 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1579,8 +1579,9 @@
 CT = TypeVar('CT', covariant=True, bound=type)
 
 
+# This is not a real generic class.  Don't use outside annotations.
 class Type(type, Generic[CT], extra=type):
-    """A generic type usable to annotate class objects.
+    """A special construct usable to annotate class objects.
 
     For example, suppose we have the following classes::