Redundant quotes in `subprocess.TimeoutExpired` message

Bug report

Bug description:

Bug description:

While looking into https://github.com/python/cpython/pull/151486, I noticed a similar issue in subprocess.TimeoutExpired.__str__.

subprocess.TimeoutExpired.__str__ manually wraps cmd in single quotes while formatting the exception message.
This produces confusing output when cmd is a list, because the list representation already contains quotes around its string elements.

import subprocess
import sys

cmd = [sys.executable, "-c", "import time; time.sleep(10)"]
subprocess.run(cmd, timeout=0.01)

Current output:

Traceback (most recent call last):
  ...
subprocess.TimeoutExpired: Command '['...python...', '-c', 'import time; time.sleep(10)']' timed out after 0.01 seconds

Expected output:

Traceback (most recent call last):
  ...
subprocess.TimeoutExpired: Command ['...python...', '-c', 'import time; time.sleep(10)'] timed out after 0.01 seconds

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-152559

Start at subprocess.TimeoutExpired.str and inspect the existing subprocess exception tests. Reproduce the timeout example, adjust the expected message so the command representation is not redundantly wrapped, and verify the relevant subprocess tests pass; linked PR gh-152559 indicates work is already underway.