bpo-40443: Remove unused imports (GH-25429)

* pyclbr no longer uses copy
* typing no longer uses ast

Issue discovered by pyflakes.
diff --git a/Lib/pyclbr.py b/Lib/pyclbr.py
index ebcc23c..37f8699 100644
--- a/Lib/pyclbr.py
+++ b/Lib/pyclbr.py
@@ -42,7 +42,6 @@
 """
 
 import ast
-import copy
 import sys
 import importlib.util
 
diff --git a/Lib/typing.py b/Lib/typing.py
index dc2a7a4..ea66cf5 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -20,7 +20,6 @@
 """
 
 from abc import abstractmethod, ABCMeta
-import ast
 import collections
 import collections.abc
 import contextlib
diff --git a/Misc/NEWS.d/next/Library/2021-04-16-02-03-00.bpo-40443.Io6FHL.rst b/Misc/NEWS.d/next/Library/2021-04-16-02-03-00.bpo-40443.Io6FHL.rst
new file mode 100644
index 0000000..f5672e6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-04-16-02-03-00.bpo-40443.Io6FHL.rst
@@ -0,0 +1,2 @@
+Remove unused imports: pyclbr no longer uses copy, and typing no longer uses
+ast. Patch by Victor Stinner.