Add fixture for ValueError.message to 2to3 tool

[CarstenGrohmann]

Bug report

Please extend the 2to3 tool to display a warning when ValueError.message is used ,or replace the message attribute
e.g. with str(<exception>), since ValueError.message no longer exists in Python 3.

Reproducer

$ cat example.py2
#!/usr/bin/env python2.7
try:
    raise ValueError('Foo')
except ValueError as e:
    print "Caught: %s" % e.message

$ 2to3 example.py2 
RefactoringTool: Skipping optional fixer: buffer
RefactoringTool: Skipping optional fixer: idioms
RefactoringTool: Skipping optional fixer: set_literal
RefactoringTool: Skipping optional fixer: ws_comma
RefactoringTool: Refactored example.py2
--- example.py2	(original)
+++ example.py2	(refactored)
@@ -2,4 +2,4 @@
 try:
     raise ValueError('Foo')
 except ValueError as e:
-    print "Caught: %s" % e.message
+    print("Caught: %s" % e.message)
RefactoringTool: Files that need to be modified:
RefactoringTool: example.py2

Example of an expected result

--- example.py2	(original)
+++ example.py2	(refactored)
@@ -2,4 +2,4 @@
 try:
     raise ValueError('Foo')
 except ValueError as e:
-    print "Caught: %s" % e.message
+    print("Caught: %s" % str(e))

My environment

• up-to-date ArchLinux on x86_64
• Python 3.10.8 (main, Oct 13 2022, 21:13:48) [GCC 12.2.0]

[JelleZijlstra]

2to3 is no longer maintained and will be removed from CPython in the future. Perhaps third-party tools like https://python-future.org/futurize.html would be open to adding such a converter.

[CarstenGrohmann]

Issue reported to : PyCQA/modernize#261 and PythonCharmers/python-future#609