gh-68583: webbrowser: replace getopt with argparse, add long options

[hugovk]

Replace getopt with argparse in webbrowser's CLI.

Also add long options for -n and -t: --new-window and --new-tab.

Add tests for the CLI (inspired by https://pythontest.com/testing-argparse-apps/), and for an error case of new().

Before

❯ ./python.exe -m webbrowser --help
Usage: /Users/hugo/github/python/cpython/main/Lib/webbrowser.py [-n | -t | -h] url
    -n: open new window
    -t: open new tab
    -h, --help: show help

After

❯ ./python.exe -m webbrowser --help
usage: webbrowser.py [-h] [-n | -t] url

Open URL in a web browser.

positional arguments:
  url               URL to open

options:
  -h, --help        show this help message and exit
  -n, --new-window  open new window
  -t, --new-tab     open new tab

Plus some cleanup:

• Fix whitespace
• Fix/use f-strings
• Remove redundant parentheses
• Use triple backticks for docstrings
• Use new-style class

• Issue: webbrowser.py update to use argparse.py #68583

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📚 Documentation preview 📚: https://cpython-previews--117047.org.readthedocs.build/

[terryjreedy]

I did not look at the new CliTest class. I have not use argparse but have read doc and examples and it looks good, and much nicer than existing. One suggestion.

[bedevere-app]

When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.

[zware]

What's our current policy on stdlib type hints?

[hugovk]

python/devguide#1304 says in general don't add, but there are some specific exceptions, but that the policy is undocumented. I think these might be okay because they're "simple" and internal, but I'm also happy to remove if you'd prefer?

[zware]

argparse allows argument shortening and handles ambiguous shortenings as one might hope, but it might be nice to confirm that --new fails properly.

[hugovk]

Nice, I didn't know about that feature :) I've added a test case.