explicitly set UnsupportedOperation's module rather than relying on incorrect...

explicitly set UnsupportedOperation's module rather than relying on incorrect globals on startup (closes #14745)

Lib/io.py

@@ -67,6 +67,9 @@ from _io import (DEFAULT_BUFFER_SIZE, BlockingIOError, UnsupportedOperation,
 
 OpenWrapper = _io.open # for compatibility with _pyio
 
+# Pretend this exception was created here.
+UnsupportedOperation.__module__ = "io"
+
 # for seek()
 SEEK_SET = 0
 SEEK_CUR = 1