Issue #13544: Add __qualname__ to functools.WRAPPER_ASSIGNMENTS.

Patch by Filip GruszczyƄski.
diff --git a/Lib/functools.py b/Lib/functools.py
index 1abb37a..092b1ab 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -21,7 +21,8 @@
 # update_wrapper() and wraps() are tools to help write
 # wrapper functions that can handle naive introspection
 
-WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__', '__annotations__')
+WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__qualname__', '__doc__',
+                       '__annotations__')
 WRAPPER_UPDATES = ('__dict__',)
 def update_wrapper(wrapper,
                    wrapped,